Etiquette

Five things that a person might do to display a lack of etiquette or good manners are: Grabbing food to eat, when it can be eaten with a fork or spoon, making a girl open her own door on a first date, shaking someone's hand when you meet them for the first time is important, slouching when having a meal is unacceptable, sitting straight is the propper way.
If I had a friend that was grabbing food with their hands and not using their fork, I would let them know that they looked messy and they needed to eat correctly, but I would be afraid to show them because I don't want to seem like a know-it-all.
If a guy didn't open the door for me I wouldn't mind too much, but I would be a bit disapointed.
Not shaking someone's hand is a sign of low self-esteem and it could make anyone look rude by not shaking someone's hand when meeting a new person.
Once again, it looks like low self esteem when you don't have direct eye contact slouching down. If my friend was doing that, I would discreetly let her know.