Well I'm probably going to get a bashing for saying this but ...
1.World of Warcraft.
Simply because I'm not into mmo's like some other people are, so I never picked up this game until 6 months ago after being at college with someone who spoke about this game all the time. He used to tell me it's the most popular, the best online game ever, great players and community, amazing quests and story.
So I bought the "vanilla game" as he called it to give it a go. Well after him hyping it up to me, it was such a disappointment. Every single quest was "go here kill x10 of this" or "go here collect x8 of this" The game was absolute rubbish, fighting was beyond a joke. Point, click, kill, rinse, repeat

such a disappointment after 2 years of this guy going on about this game.
2. KOTOR 2 ... absolute mince
3. Assasins Creed. I wanted to like this, but it was so boring
