Depends on the game, WoW is useless if you play for 2hours, OH EM GEE I DID 2 QUESTS!!!!111!
However so is Warhawk which is more like OH EM GEE I GOT 100KILLS!!!!1111!
Than comparing an RPG like Cabal Online and say COD4 than you have, Yay 3 levels and 3 new ultra rares! and Woot I just got earned 20 acheivements!
On the fun side, I much prefer a FPS than an MMORPG short term. Long term (~5 hours+) an MMORPG is lots more fun than killing noobs repetitively:3