When I started graduate school, I decided I wanted to study the cognition and behavior of wild animals in their own habitat. In my case, it's "wild" fox squirrels whose habitat happens to be a college campus.
I spend a lot of time outside with the squirrels. Sometimes it's a lot of time for very little data. Part of the reason it takes so long is that sometimes they decide they need a little siesta during an experimental session. And when this happens, there's really not much we can do...but wait. They are volunteers, after all.