Another thread where some feel it is good to tip, and others say it is an insult to tip when the tip is supposedly included in the price. When we pay our bill, we ALWAYS leave a tip, usually 10 to 15%. I have never noticed a reaction where the server was "insulted" by us leaving the tip. Quite the opposite, it seems they are always grateful, and respond with a "Thank you" or "Merci" and smile at us.
If I am out of line as a Crazy American, I would apologize to the server for being as such, but still leave the tip anyway.