Humanitarian aid
Problematic aspects: 

Economic distortions due to food aid: Some of the unintended effects of food aid include labor and production disincentives, changes in recipients' food consumption patterns and natural resources use patterns, distortion of social safety nets, distortion of NGO operational activities, price changes, and trade displacement. These issues arise from targeting inefficacy and poor timing of aid programs. Food aid can harm producers by driving down prices of local products, whereas the producers are not themselves beneficiaries of food aid. Unintentional harm occurs when food aid arrives or is purchased at the wrong time, when food aid distribution is not well-targeted to food-insecure households, and when the local market is relatively poorly integrated with broader national, regional and global markets. 
Food aid can drive down local or national food prices in at least three ways.

First, monetization of food aid can flood the market, increasing supply. In order to be granted the right to monetize, operational agencies must demonstrate that the recipient country has adequate storage facilities and that the monetized commodity will not result in a substantial disincentive in either domestic agriculture or domestic marketing.
Second, households receiving aid may decrease demand for the commodity received or for locally produced substitutes or, if they produce substitutes or the commodity received, they may sell more of it. This can be most easily understood by dividing a population in a food aid recipient area into subpopulations based on two criteria: whether or not they receive food aid (recipients vs. non-recipients) and whether they are net sellers or net buyers of food. Because the price they receive for their output is lower, however, net sellers are unambiguously worse off if they do not receive food aid or some other form of compensatory transfer.
Finally, recipients may sell food aid to purchase other necessities or complements, driving down prices of the food aid commodity and its substitutes, but also increasing demand for complements. Most recipient economies are not robust and food aid inflows can cause large price decreases, decreasing producer profits, limiting producers' abilities to pay off debts and thereby diminishing both capacity and incentives to invest in improving agricultural productivity. However, food aid distributed directly or through FFW programs to households in northern Kenya during the lean season can foster increased purchase of agricultural inputs such as improved seeds, fertilizer and hired labor, thereby increasing agricultural productivity.Labor distortion can arise when Food-For-Work (FFW) Programs are more attractive than work on recipients' own farms/businesses, either because the FFW pays immediately, or because the household considers the payoffs to the FFW project to be higher than the returns to labor on its own plots. Food aid programs hence take productive inputs away from local private production, creating a distortion due to substitution effects, rather than income effects.
Beyond labor disincentive effects, food aid can have the unintended consequence of discouraging household-level production. Poor timing of aid and FFW wages that are above market rates cause negative dependency by diverting labor from local private uses, particularly if FFW obligations decrease labor on a household's own enterprises during a critical part of the production cycle. This type of disincentive impacts not only food aid recipients but also producers who sell to areas receiving food aid flows.
FFW programs are often used to counter a perceived dependency syndrome associated with freely distributed food. However, poorly designed FFW programs may cause more risk of harming local production than the benefits of free food distribution. In structurally weak economies, FFW program design is not as simple as determining the appropriate wage rate. Empirical evidence from rural Ethiopia shows that higher-income households had excess labor and thus lower (not higher as expected) value of time, and therefore allocated this labor to FFW schemes in which poorer households could not afford to participate due to labor scarcity. Similarly, FFW programs in Cambodia have shown to be an additional, not alternative, source of employment and that the very poor rarely participate due to labor constraints.

Increasing existing conflicts: In addition to post-conflict settings, a large portion of aid is often directed at countries currently undergoing conflicts. However, the effectiveness of humanitarian aid, particularly food aid, in conflict-prone regions has been criticized in recent years. There have been accounts of humanitarian aid being not only inefficacious but actually fuelling conflicts in the recipient countries. Aid stealing is one of the prime ways in which conflict is promoted by humanitarian aid. Aid can be seized by armed groups, and even if it does reach the intended recipients, "it is difficult to exclude local members of a local militia group from being direct recipients if they are also malnourished and qualify to receive aid." 
Furthermore, analyzing the relationship between conflict and food aid, recent research shows that the United States food aid promoted civil conflict in recipient countries on average. An increase in United States' wheat aid increased the duration of armed civil conflicts in recipient countries, and ethnic polarization heightened this effect. However, since academic research on aid and conflict focuses on the role of aid in post-conflict settings, the aforementioned finding is difficult to contextualize. Nevertheless, research on Iraq shows that "small-scale [projects], local aid spending ... reduces conflict by creating incentives for average citizens to support the government in subtle ways." Similarly, another study also shows that aid flows can "reduce conflict because increasing aid revenues can relax government budget constraints, which can [in return] increase military spending and deter opposing groups from engaging in conflict." Thus, the impact of humanitarian aid on conflict may vary depending upon the type and mode in which aid is received, and, inter alia, the local socio-economic, cultural, historical, geographical and political conditions in the recipient countries.

Increasing conflict duration: International aid organizations identify theft by armed forces on the ground as a primary unintended consequence through which food aid and other types of humanitarian aid promote conflict. Food aid usually has to be transported across large geographic territories and during the transportation it becomes a target for armed forces, especially in countries where the ruling government has limited control outside of the capital. Accounts from Somalia in the early 1990s indicate that between 20 and 80 percent of all food aid was stolen, looted, or confiscated. In the former Yugoslavia, the UN Refugee Agency (UNHCR) lost up to 30 percent of the total value of aid to Serbian armed forces. On top of that 30 percent, bribes were given to Croatian forces to pass their roadblocks in order to reach Bosnia.
The value of the stolen or lost provisions can exceed the value of the food aid alone since convoy vehicles and telecommunication equipment are also stolen. MSF Holland, international aid organization operating in Chad and Darfur, underscored the strategic importance of these goods, stating that these "vehicles and communications equipment have a value beyond their monetary worth for armed actors, increasing their capacity to wage war"
A famous instance of humanitarian aid unintentionally helping rebel groups occurred during the Nigeria-Biafra civil war in the late 1960s, where the rebel leader Odumegwu Ojukwu only allowed aid to enter the region of Biafra if it was shipped on his planes. These shipments of humanitarian aid helped the rebel leader to circumvent the siege on Biafra placed by the Nigerian government. These stolen shipments of humanitarian aid caused the Biafran civil war to last years longer than it would have without the aid, claim experts.
The most well-known instances of aid being seized by local warlords in recent years come from Somalia, where food aid is funneled to the Shabab, a Somali militant group that controls much of Southern Somalia. Moreover, reports reveal that Somali contractors for aid agencies have formed a cartel and act as important power brokers, arming opposition groups with the profits made from the stolen aid"
Rwandan government appropriation of food aid in the early 1990s was so problematic that aid shipments were canceled multiple times. In Zimbabwe in 2003, Human Rights Watch documented examples of residents being forced to display ZANU-PF Party membership cards before being given government food aid. In eastern Zaire, leaders of the Hema ethnic group allowed the arrival of international aid organizations only upon agreement not give aid to the Lendu (opposition of Hema). Humanitarian aid workers have acknowledged the threat of stolen aid and have developed strategies for minimizing the amount of theft en route. However, aid can fuel conflict even if successfully delivered to the intended population as the recipient populations often include members of rebel groups or militia groups, or aid is "taxed" by such groups.
Academic research emphatically demonstrates that on average food aid promotes civil conflict. Namely, increase in US food aid leads to an increase in the incidence of armed civil conflict in the recipient country. Another correlation demonstrated is food aid prolonging existing conflicts, specifically among countries with a recent history of civil conflict. However, this does not find an effect on conflict in countries without a recent history of civil conflict. Moreover, different types of international aid other than food which is easily stolen during its delivery, namely technical assistance and cash transfers, can have different effects on civil conflict.
Community-driven development (CDD) programs have become one of the most popular tools for delivering development aid. In 2012, the World Bank supported 400 CDD programs in 94 countries, valued at US$30 billion. Academic research scrutinizes the effect of community-driven development programs on civil conflict. The Philippines' flagship development program KALAHI-CIDSS is concluded to have led to an increase in violent conflict in the country. After the program's start, some municipalities experienced and statistically significant and large increase in casualties, as compared to other municipalities who were not part of the CDD.