1. London - Too tight, no real rhythm to it, and it has no pits. Sure, it's fun for karting and low-PP sprints, but anything resembling serious racing simply doesn't work on it.
2. Nurburgring Nordschleife and variations - It's a wonderful track for hotlapping, but actually racing on a track with that little space to overtake is the embodiment of frustration. Especially in seasonals where you have to pass ten drunken AI cars to even get to the rabbit.
3. Suzuka East and Nurburgring 24h - These get a special mention, because I invariably hit the barriers blocking off the rest of the track in the former, and Turns 2-4 in the latter. I've run so many laps on Suzuka and the Nurburgring GP track that these variations just **** with my head.