Another Pet Peeve:
You wait in line to get service. Just as you step up, the telephone rings, and the person about to help you takes the call and helps the caller, instead.
This has happened to me several times in the past. And a couple of times, when the call was done, my "turn" was interrupted by a second call.
I did not let these instances pass without the tersest of remarks for EVERYone to hear, including supervisors.