I used to go with the "dont tap the glass" but that's really also telling the fish that I think he's a fish. So now I tell the berater to fuck off and STFU. That helps accomplish both my goals; make the fish feel welcome and make the wannabe shark more upset/tilted/shut up.

Edit:
Quote Originally Posted by Marty
I guess it is ok to take money off the fishes but BY GOD you cant call them a fish unless they leave?
That is excactly right. Unless you have a reason for berating them other than to make you feel good about yourself.

1. Buy a bad beat squeeze ball or something
2. make the fish feel welcome at the table
3. ???
4. profit