A few examples

The Final Fantasy series is very guilty of this (as are most RPG games made by SquareEnix). While FF doesn’t ask you to collect too much, it makes you want to level-up and max out stuff even though it has nothing to do with the main plot. It usually gives you a near impossible goal to reach and always rewards you greatly if you can get there (if not, there’s always the bragging rights). All the optional bosses are just made up goals that FF fans expect game after game. It’s the little something that distinguishes hardcore players from the rest.

The Final Fantasy series gets an OCD rating of 8/10

I hardly need to explain this one to players who have played this game, but Diablo 2 has a pretty high OCD rating. Diablo 2 had players grinding and doing whatever-runs countless times to get a special unique/rare/set piece of equipment or just leveling up for hours to try to reach level 99 which was hardly better than level 90. Reaching level 99 was hardly worth it (except for bragging rights) and the time you had to invest was crazy: it takes as many experience points to get from 91 to 99 as it takes from 0 to 91. While Torchlight had similar mechanics it didn’t manage to get a similar OCD rating and I give my thanks to Runic Games for this. I don’t really know why there’s such a big difference in their respective OCD ratings though.

Diablo 2’s OCD rating: 9/10 (I haven’t played World of Warcraft because I’m afraid of what it could do to me but it most likely has a similar OCD rating)
Torchlight’s OCD rating: 6/10

OMG I need that to live!

The biggest perpetrator of all are all Korean RPGs. They just require so much grinding it’s not even funny. Korean’s must love it, but the only experience I had (MapleStory) was too much for me (although it did made me waste quite a lot of my time).

Final word

Games with a high OCD rating consume your life and are very addictive. You should be cautious when approaching such games as you may not come back before long.