doing the dishes. i never have the patience to do them after i eat, so they pile up until i can't take it anymore. bleh. trying to get into a habit of doing them so i can get a cat and it can jump up on the counter and not knock piles of dishes everywhere.
Out of those, I'd say dusting. I have an allergy to dust and feel as though the area is actually dirtier than when I started, as if all the particles are floating around or something. I'm weird in that sense.
Laundry is a close second because it involves going up and down 2 flights of steps with a heavy basket, and my basement stairs are not 100% safe. You also can't see very well down there.