[just another ref]

On the subject of interaction with coaches, I think the setting makes ALL the difference. If you are calling a local jr. high tourney where everybody knows everybody, as far as I'm concerned you can go into the hospitality room and play cards with the coaches between games and it won't hurt anybody. Calling any varsity game anywhere, I agree activity should be kept to a minimum.

As far as input from a coach being helpful to an official, I say never totally dismiss any opportunity to learn. Think of it this way: You work in a slaughterhouse and your job is to hit the pigs (coaches) on the head with a sledgehammer. If the pig makes a simple, reasonable request, (Don't hit me until I have my eyes closed.) you can weigh it and see if it merits your consideration.
Just don't let the pig (coach) talk you into swinging the hammer with only one hand.