As a white man, we never have any idea which way it’s going to go with anyone. Could be a bump. Could be quick grasp. Could be a shake. Hell it might even be a low or high. It’s like being blind.
There should be a sequel to White Men Can’t Jump, called White Men Can’t Bump.
Always go for a fist bump, you’ll look cool and if the other person tries to shake hands, they will be the awkward one.