I've had this a couple of times. I don't mind "Can I see your boarding pass please?", but I do get irritated by "Economy is that way, sir." or "This queue isn't for you.". It shouldn't matter what class I'm flying in, politeness should be extended to all passengers! Please check my boarding pass before making a judgement about entitlement.
I know the various queue lines need to be protected, but a simple change in tone can avoid embarrassment or frustration for both parties involved.
Most recently flying back from Toronto to Heathrow in F on a 787 we needed to get bussed back to the terminal. They tried to get everybody in F out before CW, but I was sitting in 1F and was the last to *attempt* to get off. Unfortunately, the crew decided I wasn't entitled to be getting off yet, and so my partner who was in 1E got whisked away on the first bus (with a handful of CW passengers after all). I ended up in the terminal 20 minutes later than him (yet still before our luggage...)!
I don't know what's worse though: passengers who think *they* are entitled to more than everyone else, or staff who should know better...
I shouldn't let it bother me, but I don't like to judge - or be judged!