Some may argue that Paul has a great voice, but nobody can argue that he has a stupid face.
You can follow the stupidification progress chronologically by looking at the album covers and watch the transformation from a mildly normal looking youth, to the surprised Beatle.
By the time of Revolver and later Yellow Submarine the band was drawing or painting him, on Sgt Pepper and Magical Mystery costumes and disguises, were used but it was too late.
His famous, “crumpet up the butt” look was seen on the cover of so many magazines, posters and movie screens that when the beatles finally broke up, not even John and Yoko’s hairy bushes could save him from his face.
You’ve gotta Hand it to Paul, some grow old gracefully, some grow old and ugly, but with the Help! of plastic surgeons and hair dye Paul has managed to remain stupid looking for over 40 years.