(1) if you have always wanted to go to Costa Rica but have been putting it off, do not hesitate, GO! It is one of the most incredible places on the earth.
(2) remember, no matter where you are, you are a visitor, nature is the host. We were very careful our entire trip - keeping all of our clothes off of the floor and all of our bags zipped so as not to invite little critters into our stuff. On our next to last day there, in Monteverde, I got a little lazy and left a pair of pants on the ground over night and hung them up the next morning on a chair. Later that day, I put on said pants and felt a slight stinging sensation on my calf. As I shook the pant leg, the stinging moved down my calf and - SURPRISE - a scorpion fell to the floor. Now, I had never even seen a scorpion in real life, let alone one falling from my pants. After a slight panic about being stung by this menacing looking creature, I learned that he was not very poisonous and, basically, to treat it like a bee sting (and a great story to tell about our trip)!