There is a specific cadre of actors (Harrison Ford, Tom Cruise, Will Smith, Tom Hanks) who only play good guys. In the rare case they don't, it's very confusing. (Has Hanks ever played a bad guy? We guess in "The Ladykillers", the Coen Brothers' worst(?) movie. It's hard to believe is a bad guy in that one! How can Tom freakin' Hanks be a bad guy!?)
And then there is the opposite: actors who specialize in bad guys: Alan Rickman, Harvey Keitel, Willem Dafoe, Ron Perlman... Yeah, Ron Perlman! He was in that one movie... and that TV show... You know Ron Perlman, right?
What do these actors have in common? Let's just say that they are not classically handsome. Or, to put it nicer: grit. Their face has grit. Just take a look at the photo of Perlman. He's got grit up the ying-yang!
So, even though Perlman seems like a mensch in real life, whenever he, or Rickman, or Keitel, or Dafoe plays a good guy, it's hard to believe. Just like Perlman did in that one TV show... or in that one movie?