What makes a lock truly good?

I’ve spent fifty years working on vaults, and lately I keep thinking—what’s the difference between a good lock and one that just feels good? Not the kind you can pick in three minutes, but the one that holds. The one that doesn’t need to be seen to be trusted. I’m not asking for specs. Just… what do you think? When you’re standing in front of a safe, what makes you stop and say, ‘Yeah, this one’s real’?