Joan Rivers, who is 80 years old by the way, appeared on Andy Cohen’s Watch What Happens Live last night and when a caller asked which celebrity gave her the hardest time over Joan’s clothing critique, the curmudgeonly comedian did not mince words. “The worst criticism was, ugh, Gwyneth Paltrow,” Joan said, while rolling her eyes.”She came and yelled at us, but she stood up. She can’t sit down ’cause she’s got a stick up her rear end.” Paltrow, 41, recently separated from rocker Chris Martin after 10 years of marriage.