To be completely honest, I thought World of Warcraft was actually one of the worst games I ever played, and I played some utter bullshit in my time
Seein how many customers they have it's quite hard to say that without angering at least somebody...
I love a bit of grind, I love a bit of repetitive, I love (some) mmos, but WoW was just pushing it. I mean, I really liked the friggin style, the "artwork" is really cool, if you ask me. I saw that game, heard how everybody loved it, dove into it, and just HAD to stop, because it made me mighty sick beyond description.
I dont know, was there ever an MMO with this mindless style of repetitive quests? I tried SWG in its early stages, I tried AO, both had some pretty mindnumbing activities, but WoW just won the flowerpot. After I saw how this game took off, I was pretty fookin scared of my fellow gamers. (edit: on the contrary I really loved Ultima Online because it gave you the opportunity to actually do stuff "outside the box" and just generally enjoy yourself, doing whatever tickles your fancy. I think it was the only mumorpuger in which I actually roleplayed. In WoW even fishing gives you that Treadmill feeling that doesnt go away.)
High level, and "complex" teamwork requiring content may be funnish, but there are myriads of games which do this better, imho.
At any rate, it's not actually the worst, but for me the discrepancy between how much people like it and how much I think it should be liked is definetly the greatest when it comes to WoW.
That and combustion engines, but that is a different story.
Oh and fighting games! They are all bad beyond description, if you ask me. Because they just make no fucking sense! I heard there is some samurai game which is pretty accurate, I like toribash on the "proper" settings, and I like Street Fighter for its fun arcadey style as well as Mortal Kombat 1 and 2 because they pulled off that hype so nicely when I was exactly at that certain age (14)... but generally I think fighting games are actually bad.
Toribash being the exception, because it does nothing of the things I hate in your average fighting game.
And I'm not talking about sidescrolling arcadey beatemups like Double Dragon or Final Fight or even better, the great TURTLES IN TIME (all hail to TMNT) on the SNES. Those were just awesome, stupid and fun. Good times.