This is the reason I ask:
http://amarillo.com/news/local-news/...e#.Tp_AyM1nFby
Caused an emergency landing. Not a single passenger did anything about it... other than a Navy vet that considered maybe doing something, after he put his shoes back on of course.
To me, that's pretty disappointing.

Also an interesting side note that the guy was Iranian, after the recent happenings with US/Iran/Saudis.