"Because"

Jon and I have a new problem on our hands with Derrick! It all started about 2 weeks ago. I went to go give Emma a bath, leaving Derrick at the table to finish his breakfast. (We all know that doesn't go so well anyway!) I called down the hall to see if Derrick was eating. I heard him yell back, "No, I'm just taking my shirt off!" What?! So I walked into the kitchen and couldn't help laughing. There was Derrick in his chair and he had managed to take his shirt off and it was hanging around his waist. I asked him "Derrick why did you take your shirt off?" His answer,"Because!"
Now, keep in mind he has never tried to undress himself before. I think he is just excited that he finally figured it out! Moving on! Last week I went into check on Derrick before I went to bed and this is what I found...
Derrick sound asleep with half of his pajamas off! I thought it was too funny to not take a picture! A few days later Jon and I went in to check the kids together. When I opened Derrick's door my eyes were adjusting to the dark and I saw what I thought was Derrick on the floor. Then I saw him move in his bed. We walked in and started laughing uncontrollably! There on the floor were Derrick's pajamas AND his pull-up! He was just laying in bed completely naked! When Jon and I finally stopped laughing Jon asked Derrick why he was naked. His answer, "Because!"
So, we have been having long talks with Derrick about how he needs to keep his clothes on! My sister babysat for us the other night and I forgot to warn her about our new little problem. I asked how things went when we came home and she said she went in to check on Derrick and found him with just his shirt on and his pants and pull-up were on the floor. Guess what his answer was when she asked him why? "Because!" It is a little strange to me that he only does this at night. He never tries to undress during the day except for that one day at the table. He never tries to do it during nap time. I'm not sure what it is about bedtime that makes him want to be naked! It's not the worst of our problems...it's actually pretty funny. But, I hope we can solve it soon!