He just can't come up with any jokes himself.
If you were in my lunch and sat at the table with me last year, you may know about this quaint little story of Matt Day threatening me by, "... drilling me in the head with a hammer." Or something of that sort. Basically, he wanted to take a screwdriver/drill, put it on my head and it it with a hammer as illustrated by the picture below.
That was the picture drawn of Matt Day and Mike Kehoe. It's lovely, isn't it?
Anyway, I was watching "The Simpsons" season 6, episode 2 and I just saw Homer break a clock or something using a drill which he then hammers into the clock.
So, either Matt Day is really bad at jokes or he just isn't original. Hell, it is possible that both are true considering the one joke about getting my hair cut at a toilet shop. (Apparently, this is from some sort of bad movie.)