2-year-olds are easy. They haven't yet learned how to really push your buttons and cause mayhem. For example, they can't throw things really well yet. Wait a year or two...
Kids are impulsive, no matter what you tell them, how many times you talk with them about proper behavior and how to solve problems without shoving, kicking, hitting, pinching, throwing things at their younger siblings, because they wanted to play with your purple pony instead of the red, blue, yellow or white pony. Or she'll get in her mind to horse around and run around the house until she runs into a doorknob or something which will result in the umpteenth discussion about: "why did you do that? I told you you're going to hurt yourself" while she cries her lungs out.
The older they get, the more potential for mayhem. Wait till they can drive a car...I shudder at the thought.
You can't control your kids 100% of the time (after they learn how to walk), unless you put them in a straightjacket (yes, thought of that once or twice). They will hurt themselves, they will hurt others, they will probably hurt you, they will misbehave, they will drive you crazy. And when they do, only saints don't think about doing crazy things.