A few things I've learned traveling in Latin America:
1) Riding in the back of a pick-up truck can be a fun and easy way to travel, but your ass will never be the same.
2) Wearing a flashlight on your head is not geeky. It's practical.
3) Bad movies are better when dubbed into Spanish, but Bruce Willis movies stink in any language.
4) You don't need to wash your clothes as often as you think. Or your face. Or your hair.
5) Always ask directions more than once, because the first person is often wrong. And in some places (for example, Coban), everyone is wrong. And everybody claims not to be from there.
6) In any language, children are smarter than we are.
7) Dogs on rooves, swimming in waterfalls, the sight of someone carrying a machete on their belt, the occasional afternoon volcano eruption, having a woman with a basket of tortillas sitting in your lap for hours on a minibus surrounded by 30 other people, all of these things can eventually become "normal."
8) Always keep your bags zippered because you never know what might crawl inside.
9) There is such a thing as decent wine in a box.
10) Once you've seen one monkey, you've seen them all.