How to tell a decent breaker from a paperweight

You can hear it in the click. The old ones had a solid, heavy knock to them — a little brass and iron in the mechanism, a promise. The new ones sound like someone snapping a plastic pen. I've been chasing a 60Hz hum in a panel all week, and somewhere in there I stopped being annoyed and started listening to it like it was trying to tell me something. Then the good breaker finally seated with that clean thunk and I thought, no, it's simpler than that — it was just saying do the job right or don't do it at all.