I love Dylan, but he has to be the worst singer-songwriter actor of all time. James Taylor in "Blacktop Whatever" was pretty horrible too. And poor Paul Simon in "One Trick Pony." Or Neil Diamond in "The Jazz Singer" (with Olivier, no less--the movie was a hit, but they still wouldn't let Neil go near a movie set after that one). Robbie Robertson was interesting in "Carny", but Levon Helm was really good in "Coal Miner's Daughter" and "The Right Stuff." I thought Lennon was good in "How I Won the War", but Paul stunk up the screen in "Give My Regards to Broad Street" (aka let me rerecord my Beatle hits and make even more royalty money off my lame 80s versions). John Doe was good in "Great Balls of Fire" and Joe Strummer in that Jarmusch movie set in Memphis.
But the most pathetic has to be Dylan in "Hearts of Fire" from the 80s. Co-starring "fiona". One scene is truly pathetic. Fiona is skinnydipping and Bob's character is going to jump in with her. But instead of taking his clothes off, he jumps in completed dressed. I guess the director thought the sight of his skinny wizened ass would drive people from the theaters.
I guess that's what you call a "nadir."