VexNet: what's so gross about coughing/sneezing in your palm is that even if you do wash your hands afterwards, you are most likely to open a door or two and touch a few objects before you reach the bathroom. To me, your sleeve, your shoulder or the bend of your arm is to be prefered in case you don't have a handkerchief with you, since those areas are less likely to come in touch with anything/anyone.
Some other things that grind my gears: headaches, hurting throats and having the need to sleep. Just imagine everything we miss that one third of our lives when we lay snoring.