Among the most important things to remember are the rules of airplane etiquette. We can't decide if the limited space, the attentive flight attendants, or the restless passengers are to blame. One thing is certain, though: you should never, ever attempt to secure an upgrade at someone else's expense. The story below is an account of a frustrated traveler. The original poster (OP) had bought a ticket from New York to Hawaii. He made sure, well in advance of the holiday, that he would have a seat…