I've decided that by the time babies are couple of years old, they are furious.
It's because they've spent their whole life all cooped up in a little baby body with no good control over their muscles and they can't speak. Can you imagine how frustrating it must be to be hungry, tired, sleepy or shitty-bottomed and not be able to say anything about it? Or to teethe? What a bitch it must be to have stuff ripping out of your gums while you don't know what the hell is going on.
So, kids get big enough and get to where than can express themselves in new ways and use that to let us know that they are some angry individuals. They have their happy times but that is to just lull us into a false sense of security.
I think I'm going to go to school to be a toddler therapist. I think this is a huge untapped market.