Hmm been a year, time for an update I suppose.
3/4 sliders on 1/4 that do not fit with the music (which is pretty much all of them). One or two of them here and there to add more variation is fine if they fit well enough with the music. Too many can kill the rhythm of the map. Example map =
https://osu.ppy.sh/s/75509 (Insane)
1/4 (or 1/3 for that matter) stream jumps. Plays like crap 99% of the time. Example map =
https://osu.ppy.sh/b/153926# (Expert),
https://osu.ppy.sh/s/39428# (Insane).
Slider streams, by that I mean 1/8 sliders mapped as a 1/4 stream. Example map =
https://osu.ppy.sh/b/169841&m=0 (Grumd). Plenty of them in there.
Pretty much any or all of those in a map will make me quit the map mid way and not play it again for a while (if at all). Slider streams and 3/4 sliders are annoying but I can still enjoy them occasionally. However, maps with stream jumps will never be higher than a 3/10 in my opinion, and that's being generous.
EDIT: I also really hate it when mappers put stupidly hard parts immediately after a long break. Pisses me off more than anything when I SS a song up until a break and then immediately miss. And while we are at it, I hate songs whose first note starts on the first audible part of the song so I have to retry the song like 8 times to not get a 100 if I am playing on hidden.