Comedies that just fall flat at EVERY LEVEL. The jokes aren't funny, the director has no control over the actors who are all doing their own thing, there's no real story, a lot of the jokes are cheap, the pacing is off, the tone is all over the map, and you can actually feel how mind numbing the whole thing is just by watching.
I think Teen Wolf Too was the first "comedy" that was so bad I started feeling ill watching it. I guess the modern equivalents would be the unrelated American Pie sequels, the Date Movie/Epic Movie that think they're parodies but are just referencing other movies as the joke, and the bottom of the barrel that is White Chicks, Taxi, etc.