One was a lag in the Finder that occurred (apparently) randomly, accompanied by something that appeared like a memory leak to me. Finder windows took 20s or so to become frontmost when clicked, and Finder was consuming a two-figure amount of memory at those occasions. I think it was related to the iCloud sync, because most of the time it was OK after killing cloudd. (But I might as well be wrong, since some months ago I said Dropbox was the culprit. Anyway, it is gone now.)
The second one was a continuous auto-destruction of the pbs preferences (the pbs.plist file). This is the file where all your shortcuts for the Services are stored. (System Preferences > Keyboard > Shortcuts > Services).
Each time I changed a shortcut everything has been reset to the defaults. You imagine the annoyance!?
I worked around it by tracking any changes to that file by Hazel, so I could restore it. Furthermore some shell commands like /System/Library/CoreServices/pbs -flush en seemed to be useful, before touching any shortcut.
As said, both gone with 10.13.