After Haiti won its independence in 1801, most of the world's powers sided with France against the new republic.
Although Haiti actively assisted the independence movements of many Latin American countries, it was excluded from the region's first meeting of independent nations in 1826.
The United States did not recognize Haiti, the second republic in the New World, until 1862.
The indemnity demanded by France in exchange for diplomatic recognition was not completely paid until 1947, and was only made possible by taking out other large loans.
Haiti has been invaded and/or occupied by military forces from the U.S., Britain, and Germany. The American occupation, 1915-1934, included brutal reactions to any Haitian revolts. Over 2000 Haitians were killed in one skirmish.
In 1937, the Dominican Republic's dictator, Rafael Trujillo, ordered his Army to kill Haitians living on the Dominican side of the border. Between 10,000 and 20,000 Haitians were massacred in three days.
In 1982, after African Swine Fever had spread to Haiti, the Haitian government, spurred by the U.S. and Canadian governments, began the extermination of the native stock of pigs. Promises were made that a better breed of pig would be introduced. But the "better" pigs were not as hearty, required imported feed, clean water (unavailable in most of Haiti), and roofed pens. Haitian peasants quickly dubbed them "prince a quatre pieds" (four-footed princes). One observer estimated that in monetary terms, Haitian peasants lost $600 million to international expertise.
Rice has been cultivated in Haiti for over 200 years and is the staple food of Haiti. Until the 1980s Haiti was self-sufficient in its production of rice. At that time, Haiti was pressured to lower its already to 3%, which is lower than the tariffs in most other Caribbean nations. Haiti is now flooded with U.S. rice imports, causing devastation to the Haitian agricultural economy, which in turn drove many farm families into cities - like Port-au-Prince.
More examples abound, but I'm quickly exhausting my 400 words. And I haven't even gotten to the issue of political instability.

Pray for the people and the future of Haiti.