There’s always the story from the filming of Marathon Man, where Dustin Hoffman was doing all his Method stuff and physically beating himself up to look beaten in the role … and Sir Laurence Olivier just looked him up and down and said, “Have you tried acting, dear boy?” 
That takes a bit to build up, but great ending!
Based on just that photo, I’d say the guy on the far right pulls off “cool” better than Winkler, Stallone, and the guy on the left.
That’s Perry King, who was indeed pretty cool. He auditioned for Han Solo, and played him in the NPR radio adaptation, among a great many other roles.
I love Spielberg, but as the quintessential Boomer director, he was the absolute wrong person to make a movie about Gen-X cultural touchstones.
The shyest adult I ever knew was a professional actress for decades, specializing in starring roles in Shakespeare and Tennessee Williams. The most lady-killing actor I ever knew was gay. I’m a computer programmer, but, for over 20 years, I was also a professional opera singer. An actor I know is the world’s #1 expert on the life of Edgar Allen Poe’s mother.
Never assume anything about an actor; the whole point of the profession is faking it.
Well said.
Robin Williams was a huge fan of World of Warcraft, and played it quite a bit.
A lot of it depends on looks - it’s not just acting skill. Cavill, Diesel, and Fillion all look like jock types, and that makes it easier for them to play someone very mainstream and not cool. OTOH it’d be hard to imagine Rick Moranis playing someone conventionally cool.