My first thought is fighting games... usually there is too much dedication to memorizing combos for like 30 characters. Games like Tekken and the new street fighter, virtua fighter, marvel vs capcom, and blazblue, etc.
Only fighting games I really like are Dead or Alive series and Soul Caliber series because a new player can button mash their way to victory, especially in Soul Caliber. A Dead of Alive veteran could counter every move you throw though. I used to do that in DOA2 to my friends. haha.
But since I am good at a few fighting games and I do really enjoy them and beating up my friends I'm going to have to change my answer and say my hardest genre is sim racing. I'm looking at you Gran Turismo. I prefer arcade style racing. I hate needing to go into 2nd gear to make a turn at 30mph. Give me a chance to make the turn at 100mph!! I remember in GT3 I would just go straight into the wall.
