The introduction of achievements had a strange effect on me. At first blush, I thought they were just goofy pop ups that interrupted my gameplay. I didn't care about my gamerscore or fully "completing" a game at all. After a while though, I was on achievements like a fat kid on a cupcake (read as: myself on a cupcake). Suddenly every trivial task was semi-rewarded and acknowledged. Before long I was going out of my way to do menial tasks just to get my fix. Xbox somehow turned me into an overachiever.
Advice to Parents/Spouses/Significant Others of gamers:
If you want to see a dent in that tedious to-do list, trick your gaming loved one into chores using the same system. If I saw that blessed little gray dialog box every time I did laundry, mowed the lawn, or washed the dishes, our house would be immaculate. Achievements make us feel like we've done something impressive, even though we didn't really want to do it in the first place.
(P.S. Please don't forward this post to my wife. I enjoy weekend loafing)