Battlefield Bad Company. Ignoring that there is a glitch that prevents the platinum for most people, even if the glitch didn't exist the amount of multiplayer in-game achievements (need get them ALL for real achievements/trophies) is huge.
To make things worse a load of them are very time consuming, like even if all you did every single game was try and earn those achievements...it would take hundreds of hours, just for a particular one.
The worst is run 50 people over with a boat. There is only one map that this can be done on, and that map is split between two different game modes, on one mode no one ever goes in the water ever, no reason to. The other mode people need capture an island but no one is ever stupid enough to try and swim it. Then there is the fact the boat/player hit detection is crap so most of the time when you run them over you do not even kill them and by the time you turn around they will reach a shore, if someone didn't shoot them. In months playing that game I probably only ever saw a hundred people swimming at most.
That is just one award you need earn.