Overheard while being vectored to the ILS 10 at KMSY the other day:
Approach: Jet 123, maintain 9,000.
Jet 123: Um, ok, we're gonna go through it.
Approach: That's ok, climb and maintain 10,000.
Jet 123: Uh, we're on our way back down to 9,000, now.
Approach: Well, 10 is available, you're welcome to climb and maintain 10,000.
Jet 123: Why are you doing this to us?
Approach: Well, I'm trying to separate you from traffic behind you, if that's OK.
Jet 123: That's fine, but we just zero-g'd an aircraft with a US Senator aboard. We'd rather not squash him, now.
Approach: If I'd known that, I'd have sent you back down to 5,000 first.