Around eleven, the restaurant empties and the bar fills. The cooks come out of the kitchen, the waiters loosen their ties, and the bartender, who has been working all night for other people, finally makes a drink for himself.
This is the bartender's hour. The music changes, the orders get more interesting, and the people sitting at the counter are mostly people who work in other bars. If you are allowed to stay, stay quietly.
Ask for something off the menu. Ask what they would drink. Tip well, and come back on a Monday, when the hour starts earlier.