I do finish a lot of games but i'm not religiously committed to completion. Some games just aren't worth the time sink when I could be learning Chinese or reading the Bible or something. I won't finish Killzone Shadow Fall and probably won't finish my latest file of FFI.

One issue that comes up with PSN and Steam sales is I'm buying "Complete Editions" more often than not. How much of the DLC am I obligated to play before considering the purchased title "finished?" I typically just beat the vanilla game.