I Wonder Which Planet He Left His Memory On? :)

The Doctor (my father) has an (extreme) element of forgetfulness about him. He says he has a brain like a colander, and when I was younger, I said the hole was bigger than that, and playfully nicknamed him "Ol' Hula-Hoop Head"! I've grown out of that now, and have decided that it's more like the absent-minded-professor brain of the Doctor. I've gotten into the habit of calling out each night, "Goodnight, Doctor!" when I get into bed, and at first, he'd reply, "Goodnight, Sarah!", but he got confused and often called me Elisabeth or Susan! Then he decided I was more quick-tempered than Sarah, and started calling me Leela, although more often than Leela, he calls me Leesa, Louise, or Layla! A few nights ago, however, he simply said, "Goodnight...uhh... Whatever!" His forgetfulness can be less insulting, though, such as when he walks right past the ketchup, staring straight at it, and then says "I don't know where I left the tomato sauce!" :) He's also in the habit of constantly losing his glasses. It's like the sonic screwdriver! Almost every night he says "I've lost my glasses! Where did I put them?" to which I usually reply, "I found your glasses!", and hand them to him (remember "The Sontaran Experiment"?). :)
I wonder what else is taking up so much of his mind... Maybe he's trying to save the earth again. Who knows where he goes during the day? He says he's at work, but "work" could be talking to the Brigadier or something. :) I've never been inside his office, and I must say it looks pretty important from the outside! :)