Top Ten Don'ts For Meeting Aliens:
1.Don't attempt to shake hands. What appears to be their hand may be some other appendage.
2.Don't smile. Showing your teeth could be construed as aggression.
3.Don't offer them any alcoholic beverages. Even if alcohol isn't toxic to them, the last thing we need is an intoxicated alien crashing his ship into the earth. Don't let them drink and fly. (The same goes for drugs - prescription or otherwise.)
4.Don't offer them food unless they demand it. You have no way of knowing their tastes and their reaction to your best meat loaf may not be what you'd expect. ( If they eat the dishes don't make a fuss.)
5.Don't try to recruit them in a multi-level marketing scheme, try to sell them any Florida swampland or the Brooklyn Bridge, or rip them off by other means.
6.Don't assume just because they're space travelers that they will be good ambassadors or even smart. Remember where most of our own astronauts come from. They may be military types with little or no social graces. ( No jokes please, their sense of humor may be totally "alien" or even non-existent with no sense of irony or sarcasm.)
7.Don't swear, use expletives or use colloquialisms, which they won't understand or worse yet, may take literally,such as "Well, ---- me!".
8.Don't take personally any slights they seem to make. They don't know our customs either and they could just be having a bad day or suffering from jet-lag. Remember how you feel after a long flight.
9.Don't exhibit any disgust at their appearance or behavior. You probably seem just as disgusting to them.
10.Above all don't piss them off. Go along with whatever they want. Close your eyes and think of Earth.
GOOD LUCK!