For me is definitely Gaunter O' Dimm

I don't often play Open world games and am not really a fan of them because I know that there will be unnecessary walking between locations, and I hate that a lot. Also, most games simply make you do the same things in the side missions and become boring quickly.

But Assassin's Creed 1 is the game I literally hated every minute of it. The open world was just boring with nothing interesting, and the side quests were all the same thing over and over... The second game is a much better game, but still, it was repetitive also and side missions were boring.