I think everyone is shocked when they first encounter the consumer market face to face. I know I was, and I know colleagues were too.

You come to accept it, though, and not take it personally. Nor try to rationalise most of it. It's really difficult at first, I remember.

Pick the things you wish to defend, and especially those you wish to attack, very carefully. The vast majority of petty threats come to nothing, so don't fan the flames. If someone is persistent, then they likely have a real issue or they are psychotic.

There's a lot to be learned, personally, from these experiences, and it will give you a new respect for hardcore sales people.