I guess like any other "addiction", you have to realize it is effecting your life in a negative way before desciding to quit.
Technically, a video game can only be considered a pseudoadiction. Either way, though, it makes me grind my teeth when people blame Blizzard for their life sucking.
Well, it's obviously not a physical addiction, unless Blizzard adds nicotine to their CDs. However, I think it can be considered a mental addiction, especially for people who are easily sucked in.
There's no exaggeration when people talk about losing jobs, falling grades, girlfriends, etc. It does happen, and I've seen it happen. But on the other hand, it's their own fault. If it wasn't WoW, it'd be something else. At least with computer games there's no physical aspect.
Of course, one guy I used to go to school with (brilliant guy, straight A/A+'s, didn't graduate) started playing WoW and doing real drugs, pretty much all the time (instead of going ot school, etc). I sort of lost touch with him after he totally stopped going to school.
But no, I don't blame WoW. I blame stupid people.