Like everyones post here, my experience (both as crew and passenger) is anecdotal.
I'm a number 1 and relatively young at 28 (ok can't say that for much longer) but it is quite surprising at how passengers attitudes can be towards certain crew. When I have a more mature crew, say late 30's and older) passengers generally are a lot more polite. However a lot of younger crew are spoken to like
sometimes and I am of the firm belief that this is because people feel it is either more acceptable or that they are able to get away with it. Such is the negative perception of young people these days. By contrast I find older people much ruder. Complete generalistion of course but that is my experience. I can kindly ask passengers to do something using sir/madam and I can be snapped at or questioned. Younger people tend to not be like that.
By the same token, I know an older female crew member is rude on a regular basis to passengers. Younger crew tend to be more enthusiastic and friendly, if not necassarilly the best at the job. One thing about some younger crew is that they can be good at the job, friendly and polite but not always the most professional. If that makes sense.
I do also think that perception plays a huge part. One thing I am aware of at work is that many people will be judging you....... we have a captive audience. It's amazing how many people I catch just watching me like they would a film. Nothing wrong with that but it makes me very self conscious. But it was particularly evident one day when a older passenger retorted as she disembarked that I need to smile more as I look miserable. I am professional and polite at work if not the most smiliest person but it goes to show that the passenger, despite being slightly rude, and even though I was polite and efficient, still took me the wrong way.
I'm not trying to excuse rude crew but I just thought my experience might add something to the debate.