You're getting warm. You may have this trait, DMC;

Another clue for the bonus question: Laurel and Hardy do not have this in common, but Abbot and Costello do. Justices Alito and Scalia share the trait, but they are the only present Justices who do. The only president with this thing in common is Grover Cleveland. Simon and Garfunkel, yes yes; Sonny and Cher, no no. Oscar winners Jack Nicholson and Meryl Streep have it while Oscar winners Robert DeNiro and Halle Berry don't. Literary figures with this trait include Stephen Crane and Norman Mailer.