I think it is a lot friendlier for us to be on a first-name basis with the FAs. Why try to establish some kind of superiority complex? True, we are customers of their company, and should be treated respectfully, but the fact is that we're all stuck in the same metal tube together. I do not see calling us Mr. or Mrs. as a necessary prerequisite for showing respect while on board. In fact, as a (relatively) young person, I sometimes get a bit uncomfortable when a FA who is many years my senior starts calling me "Mr. xxxx."

Now, the TAs, GAs, and AC reps are another story. I can see why one would want to be called Mr. or Mrs. on the ground. (or Ms.--sorry, almost forgot!)