You know why guys like Robert De Niro and Joe Pesci do a lot of mob movies? Because not every actor can play a mobster. For example, Dennis Hopper, Barry Pepper and John Malkovich cannot play mobsters. How do I know this? I watched “Knockaround Guys” (2001), in which Hopper, Pepper and Malkovich try to play mobsters. The plot (some mob-related stuff goes wrong) makes sense but the dialogue is incomprehensible. Hopper and Malkovich wrestling with Brooklyn accents is painful, but I couldn’t figure out whether watching wannabe mobster-actor Pepper try to play a wannabe mobster was surreal or excruciating.