Recently while traveling from New York to San Francisco, I sat next to two women in their 20's who made the 6-hour flight an ordeal for me. They never stopped talking during the entire flight. When the stewardess came by to pick up their trash, the woman closest to me dropped her plastic utensils and cup with some liquid leftover on my lap and didn't bother to apologize. As if this was not enough, she flatulated in her seat and left a stench all around. Of course she had to go to the restroom after that but would not transfer her laptop to her seat from the folding table to make room. So in order to get out of her seat, she stepped on my seat with her dirty shoes. And these women talked like they were well employed and the most offensive one indicated she worked in IT, a job which requires considerable training. You never know these days who you'll sit with so it's best to spread the word around about plane etiquette and hopefully someday, we'll all have a pleasant flight. :)
Below is an article from Lonely Planet Blog about How not to behave on an airplane: a passengers' bill of rights, the results of a survey. You'll be able to relate to many if not most of the annoyances which plague plane passengers today.