Tell them to fck off
Look at the messanger before the message.It usually shows its not worth bothering with.
I would say "Wow, you know everything about life hotshot... please teach me to be as great as you are.... please please please... I beg you... I don't know how will I live the rest of my life being the small me compared to a hotshot like you.... oh, do you have any books, or dvds teaching people how to become famous, wise, nice, and as cool as you are... please send me the link... I'd pay...." While saying all this, be as relaxed as you can be, and say all this while you have a big smile on your face... don't every act with body language or face ex
Good luck, and if you take my advice, let me know how it went ;)
First tell them you found what they just said offensive and if they continue in a negative manner come up with a quick clever insult and then walk away.
It's their problem and has nothing to do with you.
I call them on it.
Depends on the person, and why they felt they needed to do so
I just take a walk.No reaction.