I always give a tip to the guys that deliver furniture and kitchen appliances.

Always tip the bartenders at my local hangout before I leave. They know I tip well and I get a few free ones during the night. If I'm not at my regular spot, I give a nice tip after the first round and a little more before I leave.

Here is a problem I have sometimes. I go to a restaurant and the waitress takes my order. A different person brings me my salad and a third person brings me my entree. The waitress comes by and asks if everything is ok. Later, she brings the check. All she did was take my order, to me she hasn't done a thing.