Guys, we're paying passengers. We're on real (expensive) tickets, went through security (probably with SSSS!), and have seat assignments. We're just part of the herd.
If it's that important for us to "check in," then we should be pre-boarded. Besides, we're only going to hold up your boarding if we insist on stopping the flow to come up and say hi! What would I do with my bags in the meantime -- leave them in the aisle while the FAs have to retreat into the galley? Or leave them in the jetway, and have to push my way back out to get it after I've "checked in"? It just isn't practical unless you're standing at the cockpit door greeting passengers. If you are, of course I'll say "hi!" But I'm not going through all of the above, or waiting 'til the end and losing all hope of an overhead bin. If you
really want to talk, come on out and have me pre-boarded into first class. I'll be happy to oblige!
We wear a vaguely airline-looking uniform because our company requires us to do so on the way to an assignment, but we're not jumpseaters.