In any rate, I took the elevator ride from hell this morning

When elevators get look on oil, they "cavitate" and suck in a lot of air. The sensation for you, the rider, is that the floor vibrates and there is a humming noise. The lower it is on oil, the more the floor vibrates and the louder the humming.

@guerrillarain I assume you mean "low".

It's amazing how many problems cavitation causes.