There are a few corners at Monaco which suck, namely the chicane after the tunnel (turn 10), and the last two bends before the front straight (turns 17 and 18). I've been playing F1 2017 lately and struggle here big time. But to show it's not all bad, I really love the flat out, ballsy approach at turns 13 and 14.
For PC2, a section which really throws me off are the Spa chicanes, turns 19 and 20 - horrible in every way! Brands Hatch turn 1 is also a pain, as is Fuji's Dunlop hairpin (turn 10 into turn 11).
My favourite are the high speed, flat out kinks at Bathurst (turn 20 after conrod straight) and the right-hander after the hairpin at Hockenheimring (turn 7). Easy to take flat out in slower cars, sometimes a bit hairy in the faster cars, especially when you need to set yourself up for the subsequent slower corners. Awesome feeling every time (flat throttle, high speed, wide turn, line up, brake hard for the next bit!)
Tracks that just suck overall include Circuit of the America's, Brno and Sonoma Raceway.
Tracks that are enjoyable a million times over include Long Beach, Imola and Catalunya