As far as physically, calluses are the proof of someone's work.

[ Pulling off his own glove to hold out his hand, pointing out his own. ]

Mine are from volleyball, so they've got a specific pattern. Silver works harder at it than me though, so his are more obvious.

If you've got them, then it's obvious you went through some kind of training physically. For mentally, I think the way you analyze stuff is pretty obviously telling.