Is anyone else really lame at completing games?

I've managed to resist buying any new ones until I've completed the ones I already have, however, my attention span is very short so I never get round to it. Still got to get through Assassin's Creed, Halo 3, GTAIV, aarrghh! Maybe games should be shorter. I'm also thinking I'm not allowed to buy sequels until I've completed the original..