What the HECK possesses you to do that??!??

Kids are fun to watch... They have no qualms about a lot of things. They are dead nuts honest and will get right to the point even if it hurts. And they have the social graces of canker sores when it comes to certain things and they have NO control over the things they do sometimes... Even THEY look like they don't understand it. It's weird. They see something or are watching something and something possesses them to act and DO something. I once watched my youngest son picking his nose... He pulled himself out a winner, and looked around, couldn't find the tissues, and wiped the mess right onto the couch pillow, looked up and saw that I was watching and cried about it for half an hour. I don't know whether it was because he got caught or because he felt bad because he knew he did wrong, or a little of both, but there you have it.
My daughter poked Otis in the eye simply to see his reaction, my eldest son squished a bug that was minding its own business, my middle son dumped out his dinner on the floor because he didn't want what we were having that night...
So I ask, "What the HECK possesses you to DO THAT!" The answer is always the same... It doesn't matter which kid it is, it doesn't matter what it was that they did... It's always the same answer... "I don't know...."
Strange thing is... I believe it sometimes... Sometimes...