Journey by Stephen Clark  
    to Ridgetown You shook the alien's hand

According to Glorrzapian custom, it's a sign of goodwill to extend one's hand to someone, but there's no shaking involved. The hand is the most delicate part of their anatomy, in fact. So when you give the king a firm handshake, he cries out in pain and falls to his knees, nursing his injured hand. Several of the king's bodyguards rush forward. What do you say?
Say to the guards, "No! This was all a mistake!"
Say to the guards "Everybody get back, or I'll shake all your hands!"