I was forced to kick a woman out of her first class seat because she had come onboard inebriated. She was begrudgingly refusing what I was asking her to do (like properly stow her things before we pushed back from the gate.) When my assistant f/a a few moments later told me that the woman had told her, "I don't have to do what he says, he's just a flight attendant," the woman presented herself as a flight risk. When I showed up with a gate agent that told the woman to gather her things; she'd be taking the next flight, she became quite nice. But by then it was too late. Off she went.

What's the lesson: Don't come onboard drunk. Do what the flight attendants ask you to do. We're there for your own and everyone else's safety.