From personal experience, Ken Dodd.
We went to Blackpool for a week when I was a kid. My mum was a big fan and we went to see him in concert. Afterward we waited outside the stage door for an autograph. For hours and hours. At least it seemed that way to me.
Eventually he came out to be confronted by four wet, bedraggled people from Bolton, when he probably just wanted to get back to his hotel for a drink. He spent about 20 minutes chatting to my mum and dad and gave us all photographs, which he autographed individually with each of our names on. Genuinely nice guy.
Met Cilla Black the same week. Utter cunt.