I have this habit that whenever Ben's whining or crying because I wouldn't let him do something super fun like play with the electrical outlet, I always say, "I know, your life's so hard. You have two people who wait on you hand and foot AND wipe your butt."
However, I was thinking about it this week, and the world probably is pretty hard for babies. Take waving. We wave to say hello to people, but we also perform the exact same action for the exact opposite reason, namely saying goodbye to people. That must be a difficult concept to learn, and that's pretty elementary. Think of all the complicated social norms that as adults we just take for granted. And they shift and change depending on the situation or the people involved or the time of day. (Actually that last one I'm not sure about, but it sounded good.)
The world is a very complicated place and it's daunting to think about having to learn it all. Good thing babies don't know any better.