I have to agree with Expat Dave (I just didn't want to be the first one to be "negative"...) First let me point out that there are always exceptions. When I say there's no good Mexican food here, for example, I mean that it's pretty hard to find. You can find it but in my experience it's hard to find.
I will say that at least in years past (I don't know now because I don't eat chicken), my friend said the chicken here was really great. Not sure if that's true any more. He also liked some of the seafood (something else I don't eat).
The Mexican food here is mostly terrible. Even the Taco Bell is not even as good as the USA Taco Bell. In fact, for me, it's inedible!
I happen to like Gallo Pinto (rice and beans, with eggs or meat) but Dave is right, it's not spiced all that wonderfully. I don't eat it often, but when I do I like it. If you're into fine cuisine you likely will not like it much.
The Ticos don't even make nor use what we know as "salsa" in the USA and Mexico. You ask for "salsa" and they bring you ketchup, which apparently Ticos put on anything; ketchup, and mayonnaise. You say, "no, I wanted something spicy", and then they bring you Tabasco, or something super hot/spicy like chili sauce. If they even have that. They do have jars of super hot peppers with onion on the table sometimes but I'm always wary of eating it a) because it's usually very spicy and b) I always wonder how many used forks have been dipped into it...
And a word of warning: Some restaurants deep-fry omelettes! I've had this at least 3 times, even at an American-owned restaurant (with Tico cook)... Once I even asked, (all this in espanol of course), "Do you cook the omelette in a lot of oil?" The answer was no. Then I got my inedible deep-fried omelette delivered to me. LOL.
There are occasionally decent pizza places but if there are 10 in town, you need to try 6-7 before finding one that approximates what pizza should taste like, unless you're lucky.
But if you love rice and beans with eggs... you're in the right place!
So you make your own food for the most part! But there ARE good restaurants, it just takes a hit and miss determination and many bad meals before finding them.
(San Jose has more good ones than outlying areas; and I'm not sure about places closer to San Jose...)
So you don't come to Costa Rica for the food. You come for the nature, animals, birds, beach, friendly people, Pura Vida!