I think achievements work because they satisfy our inner magpie. It's the same reason "complete collections" are more valuable than merely "greatest hits". The

I think achievements work because they satisfy our inner magpie. It's the same reason "complete collections" are more valuable than merely "greatest hits". The extra items that make the collection "complete" may suck, but, by God, you can check ALL the boxes on the list. When I play a game with extensive achievements, the game is always fun right up until I complete the last one on the list. At that point, I almost totally lose interest. I have tried to fight that, to the point of avoiding some achievements so the character doesn't feel "done"... but it's hard. As expected, merely starting a different character can make all the achievements seem worth it again (because the checkboxes are once again empty), even though I have already done them all before.