Common vocabularies

Why is that every domain has it's own voabulary, and there's very little overlap; from software engineers to doctors to airlines? Certainly there are needs to express concepts that have no analog in other domains such as "linking" for a software engineer <nod to agregov>, but I can't imagine that my recent airline experience is one of those occassions.

I was stuck in Chicago trying to get rebooked on a flight to IAD. I had made two mammoth treks across ORD (O'Hare in Chicago is HUGE), when I arrived at the United desk. I presented a little stub of paper given to me by the USAir rep, and asked to get my boarding pass. The United agent, said "this is a receipt" and not a "ticket" I looked at the stub of paper and yes it did say "passenger receipt" immediately after is said "** ELECTRONIC TICKET **" so I said "I guess, but it seems to pretty clearly indicate that there is a ticket somewhere." So the guys pecks on his keyboard some more (felt like the seen from "Meet the Parents" with Ben Stiller at the ticket counter) and says "did the US Air rep make a reservation." I said "I have no idea... he just sent me over here with that piece of paper" He then asked for the "stub" from my last flight. He pecked for probably 5 minutes straight as I just waited DREADING another 2 mile trek back across ORD to the USAir guy. Fortunately, it didn't come to that the guy printed up a "boarding pass" scratched off "SSSS" (who knows that that means) and said "you're ready to go sir." So it ended up working out.

However, what I want to talk about is all of those terms:
"boarding pass"
"ticket"
"reservation"
"receipt"
"stub"

I don't understand why it had to be that complicated. It would seem to me that common vocabularies exist all over the place... Take for example, a sporting event, or a bus ride, or ski resort. I may have to deal with more than one of those terms, but not ALL of them. I make a reservation for a restaurant. I buy a ticket for a baseball game, which I present and I get a stub (and possibly if I bought though TicketMaster, I may have a receipt). I present a ticket (or just plain fare) to ride the bus.

Why do the airlines feel they need to have this different model? It doesn't help their customer service, or efficiency (both of which I think I've bottomed out on.... despite the fact that I'm now "Silver Preferred" on USAir, and am really close to "Gold" oooh fancy me).

Maybe it's strictly a result of complexity? Airlines are one of the few places that you can buy a ticket for an "event" and get booted because it was "oversold", or you can sit next to someone that paid half as much for the seat, or you can buy four seats (2 for young children) and you can't be sure to get them next to each other until you board at which point you have to muscle some people around. Maybe if airlines had a more fixed model (one seat, one person, one fare) then the language wouldn't be as complex?

Maybe they just want control. In the moment as I was trying to get things worked out, I was angry, really angry, but I couldn't let it all out, because they had something that I needed. The magic language decoder key required to get me on an agreeable flight. So I bit my tongue and said things like "I know this isn't your fault, but I'm just a bit frustrated by this whole thing" when what I really meant was "I think you and your airline are incompetent and I feel like punching your lights out." I was under their control.

Language can really get in the way.