Got kicked out for closing tab and tipping. Barten...

Got kicked out for closing tab and tipping. Bartender told me bluntly I did not tip enough. I explained that I was not done drinking and that I planned on continuing the night paying in cash, which of course would involve more tips. I offered to tip him cash on the spot right there and then. He would not accept my money. My buddy also offered to tip him on the spot. The issue seemed personal for some reason. Very unprofessional. Despite the bipolar bartender, the bar is nice and the location makes it seem hidden. Very nice atmosphere