While there's a lot more to be said, you'd probably enjoy checking out these previous posts on similar questions:

Why is Haiti so much worse off then the Dominican Republic? by /u/entropydecreaser

And this thread Haiti was the second independent state in the Americas. Why has its development been so lousy compared to its neighbors?

Did the Haitians really sell themselves to the devil? How do Haitians view the topic? by /u/firedrops

For extra context you might also want to read:

What caused such oppressive slavery in Saint-Domingue prior to the Haitian Revolution?