Costa Rica is a third-world country, but not in the 'traditional' way.
Many people think of third-world countries as countries where there is natural hunger or widespread disease, lack of stable government/economy, etc...
I feel Costa Rica is only third-world because of its people.
Costa Rica has everything it could need to become a "first-world" country. It has an abundance of natural resources, it has no army, it's conveniently situated for trade, a solid health care and education system; the list can go on.
The culture and mindset of Ticos is what's holding it back IMO. Firstly, they are overrun from top to bottom with corruption and greed. They need to stop the influx of Nicaraguans, Colombians and others who only cause problems and scare away tourism. They need to gain a sense of pride and ambition, instead of the "pura vida" laid back attitude/approach. They need to get out from under the heavy religious (95% Catholic?) influence.
I could go on and on but I think my point is made.