Great thread.
Genuinely one of the worst actresses I've ever seen.
I would say that some of the names in here are not bad actors but can only play a very limited range of characters and if they stray out of these roles they get badly exposed. Others are excellent support but hopeless when carrying a movie by themselves Vince Vaughn and Colin Farrell fall into this category for me.
Seen people mentioning Nicholas Cage, to me cage is a good actor with a tendency to take on shit roles. He does have a pretty narrow range, at his best in movies like leaving Las Vegas and lord of war he has been good. In movies like the wind talkers he is fucked. Michael Douglas is another, basically can play a rich guy with dodgy morals and borderline sexual deviant no better man. Falling down is the exception.
Tom cruise, blockbuster lead but he has been doing this for 20/30 years now, he's solid in the role but you never see anything special. For truly shit actors you need to look no further than Megan Fox, Vin Diesel and Andrew Garfield.
But for Michael bay been an absolute creep I would struggle to see how Megan fox could have a career, dubbing looking woman but there is a reason she is always in movies with copious amounts of CGI. Ditto Vin diesel, a career built on shiny cars.