There are really too many negatives to cover in one article and they will vary depending on you!Most importantly, you have to realize that Costa Rica is NOT the United States. It is a completely different culture and you are an outsider. Not only that you are an outsider with money. Even if you consider yourself poor, in the Costa Rican's eyes, you are rich!
The weather is beautiful, the beaches are beautiful, the mountain views are bueatiful, the rain forests are beautiful, the sunsets are beautiful. The people seem bueatiful. You will fall in love with the country when you step off the airplane.
In a year or two though all those beautiful things will be contrasted with the daily grind. The United States has a long history of being an industrialized nation bent on quality and efficiency. Costa Rica lacks that history.
You will find that things are not often done in a quality manner or with efficency. Look at how many skyscrapers are in Costa Rica. Maybe you can count them on one finger. Compare that to Panama. It is not a question of being a third world country or earthquakes.
That is simply a lack of structure that would allow such a project in Costa Rica. That lack of structure is what will eat you alive (not the insects). A lack of efficency and quality may not be an issue when you visit on a vacation or for the first months of your living in Costa Rica.
When you can't relax because life has become not slow, but convoluted and inefficent you'll understand