I've never understood this eagerness in passengers. The plane/boat/train is not going to leave or arrive any earlier because you've stood in a queue, even if you're at the front of it.
It's about bagging space in the overhead lockers - which wouldn't be a problem if people weren't taking on massively oversized bags as hand luggage. It fucking annoys me that airlines aren't stricter about that.
What also fucking annoys me (and yes, I know this isn't the rant thread, sorry, but I've started so I'll finish) is at the end of the flight when they get up and start pulling bags out of the overhead locker before the plane has even stopped moving. I had a falling out with a fellow passenger once when he recklessly pulled his bag out, dragging other bags with it. It was only my swift reaction that prevented a large, heavy bag falling on the head of the woman sitting next to me. I'm not normally the kind of person to react to other people's rudeness (far too British) but I was furious, so had a real go at him. Unfortunately, it was another very awkward 15 minutes before we were able to actually get off the plane...
Though if you wait until they start including your name you know you've probably pushed it a bit far.
I did this once. Not on purpose, just sitting enjoying a drink in the departure lounge and underestimated how far it was to my gate...