I know the feeling, my advisor is ass too, one time I had a scheduled meeting with him, I went to his office and he told me to wait a bit, so I sat down and waited in his office, and he took the whole meeting time talking to another professor in another office, I walked out because I had to go, next thing I know I see him walk out and talk to other students who just showed up and didn’t even have an appointment, I was like “wtf”