Bears: I thought it would be funny to cultivate an unreasonable fear. I picked bears. Not just fear of bears as in "they might eat me", but as in "they're plotting to take over the world." I figured I'd learn to act in a pretty realistic way even, which would be actually funny. Turns out I can't. Whenever anyone says "bear", my neck swivels around and I try to make a "funny" comment about how bears will eat you. And then I try to keep the conversation going by talking about how clever bears really are. (this only got worse after I found out Stephen Colbert had the same joke.)
Laundry: It started out actually funny, I think. Ram, Beej, and I were talking about laundry one time, and we started talking about how it takes a long time. And then we kept talking about how it takes a long time. And then, whenever someone would say "laundry", I'd go on to say how it takes a long time, and how you just don't understand because the thing is, laundry takes a long time. Somehow, they've both moved on with their lives, and I'm still pestering all my friends about laundry taking a long time.
The end result of each is that I act obnoxious. And they're traps: I can't ever actually speak about either one honestly, because that'd be a break of character. So as of right now, I'm dropping the bear joke and the laundry joke. Life's too short to tie myself to running gags that even I don't find humorous anymore.