I probably didn't earn as many achievements this year as I have in previous ones, but out of everything I played, The Stanley Parable had the best one: "Click on door 430 five times." If you haven't seen what happens, check out the video!

What was your favorite achievement you unlocked in 2013?

I think the achievements that made me smile this year are the set of achievements from Incredipede. (see achievements)

The game asks you to explore the insect world around you through a set of tasks. Once you've done them, you click 'I did it'. Once pressed the button says 'Honestly, I did' to confirm

I think that was super charming.

@noizy: That's great! Thanks for sharing.

That may be the first time I've seen a game have achievements for doing activities outside of the game. I like the whole honor system part about it; it makes me want to not cheat!