My pet peeve is those servers who are constantly stopping by to "warm" your coffee or top off the water glass, which is usually too full to start with.
I like coffee, but I don't like it too hot. I mix just the right (for me) amount of sweetener and cream and I like to let it cool somewhat and savor the drink at my own pace.
Along comes the over zealous server who proceeds to top off my 2/3 full cup (which was JUST right for flavor and temperature) and spoil my mixture of excellence!
I can vividly remember being out in a dinner party one night when the server came around topping off coffee cups around the table. I was engrossed in a conversation at the time and did not want a warm-up so I held my hand over my cup as a sign that I was all set and I kept eye contact with the person I was talking with. Well, guess what. The server wasn't watching either and the next thing I knew, I had boiling hot coffee poured all over my hand.

I jumped up and screamed, as did the server. The next thing I knew, people were pouring ice water all over my hand and arm.
As I recall, the meal was free that night.