HalPhilipWalker posted:

It also gives him something to do with his hands. It's the same reason why so many actors smoked back in the old days. Brando was famous for the things he'd come up with doing (best known example is petting the cat in the opening scene of The Godfather) in order to have something to do with his hands. One of the very practical decisions in a performance is what actors should do with their body and posture, and you don't want to just be waving your arms around while you're speaking. "Talking with your hands" looks incredibly unnatural and mannered, even back in the days when performances were really mannered.