Dr. Jekyll and Mr. Hyde

I just finished reading Dr. Jekyll and Mr. Hyde and though I loved it, I was disturbed by the fact that I've observed the same drastic changes in my son.

His Dr. Jekyll side is rule-following and socially acceptable. The other day we were at Wal-Mart and I tried to convince him to get into the basket of the cart. He said, "No. I've read the rules and they say we're not supposed to get in there."
The boy's four and can't read so I'm like, "You read the rules?!"
He said, "Yes. I read them. They're right here." He pointed to the pictures on the colored flippy seat part of the cart and lo and behold, there was a picture with a line through it of a kid sitting in the basket of the cart.

Later as we were returning the cart, he didn't want to leave it facing the other carts. Instead he took the time to turn it around and slide onto the stack. Good grief. Sometimes he's a little overboard in the OCD department.

Then, you get him angry and Mr. Hyde is terrorizing the neighborhood:

The other day Andrew couldn't go with us to tour the new elementary school because a tantrum got in the way. I asked him to step out of the car and stay home with dad. As we were driving away, I could hear him yelling hateful things to me as he shook his tiny fist.

An hour later we returned home to a gloating little boy. He looked at me with an evil glint in his eye and calmly said, "I ruined everything while you were gone." I looked in the living room and noticed the couch cushions, pillows, and blankets were all over the floor so I said, "I see you've torn up the couch. What else did you ruin?"
"I ruined everything."
"What do you mean? What else?"
"The family room, Rachel's room, and Megan's room. Everything."

I took the "ruined everything" tour and sure enough, every room was a disaster. He had pulled things out of drawers and off shelves and scattered junk all over including my bedroom (which he neglected to mention) where he had pulled things off hangers and thrown them onto the floor.

Since my Mr. Hyde forgot to take his Dr. Jekyll potion before I came home, he was still recognizeable as the culprit and his little "hyde" was put to work cleaning up the mess.

He responded with, "Now you're just making me mad AGAIN!! And that's the second time today you've made me MAD!!"

How can the little rule-reading boy be the same kid who "ruins everything"?