I'm such an Idiot

We have snow this morning, a nice amount, about 1/2 to 1 inch, so enough to look pretty but the roads are still ok, all be it, a bit slushy. I took William to school as usual, when I arrived I parked up then found my ignition key was stuck in the ignition, I tried and tried and could not get it out, also because it’s a chipped key (BMW standard) the car wouldn’t start, damn i thought, then I remembered that William yesterday had, while I nipped quickly into Boot’s the chemist, played in the drivers seat, he had locked the steering wheel, turn on lights and wipers, changed the clock etc, so i turned to him and had a right go, look I said, you playing with my car has caused this, now the key is stuck and I can’t start it, naughty boy! etc, so I walked him to the gates leaving the car as is and made him walk into school on his own. I get back to the car and call my mechanic and explained. That’s odd he said, so you’ve tried and it shouldn’t do that, then he said, what gear are you in? It’s an automatic, when I looked I had put the hand break on and left it in Drive, NOT, park, put it in park he said then try, hey presto, it’s the first time I’ve ever done that, I felt a complete idiot, thanks I said, bye.