I tip well, if the service is worth it. Most of the time, in places we eat and drink regular, it's good because they know we tip well. When it's not I tip accordingly. Places that add it as part of the bill can.
Add it as part of the price and pay the staff a decent wage.
What does piss me off is the training most staff get. My first job was trainee chef in a London hotel, the waiters and waitresses were always looking around the room to see if anyone needed them. Today you have to send up a distress flare to get service. In these cases they can get an earful if the % is added.