I don't do a lot of bars and restaurants per se anymore... The following (sent to me by a fellow player) sums up a lot of other venues I play.

10 Musical Facts for Playing in a Bar or Restaurant..

1) Unless you are in a concert situation, most of the people are not there to hear you. Your music is incidental. People go to restaurants and bars to eat, to drink, to socialize, do business, or maybe to be alone in a crowd. So if you reach some of them and entertain them, you've done a hell of a job.

2) In most restaurants, your main objective is to try to entertain without bothering anybody.

3) Any volume is too loud for someone.

4) The talent of anyone who wants to sit in is inversely proportional to how insistent he or his friends are about his sitting in. The most talented musician that you would really like to play with will be sitting there quietly and will have left his axe in the car.

5) The crowd would rather hear a terrible rendition of 'Sweet Caroline'; than the tastiest arrangement of one of your originals that they've never heard before.

6) The customer who asked for 'Sweet Caroline', his favorite song, won't realize you're playing it until you actually reach the word 'Sweet'.

7) Someone in the crowd will have halfway heard you play 'Sweet Caroline' and it will remind him of the song so he'll request it right after you've just played it.

8) Unless you want to marry her and be the one who takes her home every night, don't hitch your star to a girl singer.

9) Every black horn player who wants to sit in; used to play with James Brown or "Brother" Ray.

.....And the number one fact of life in playing in clubs and restaurants.......
Your slowest night, with the most obnoxious crowd and the worst response, is immeasurably better than the best day you ever had at a day job!!!

Eddie