I agree with this 100%. But what if someone came into your restaurant and one of your patrons started trouble with him/her?
If a new customer came into my business and one of my regulars started causing trouble with him/her for no reason than that regular customer, no matter how good of a customer, would be out the door. Businesses are succesful from word of mouth. If you throw out the new guy for an unjust reason than he will most likely tell his friends that its not a good place.
How many times have you gone out with a bunch of friends and said 'lets go to this place' and one guy says 'no, ive been their before, its no good' and everybody says 'ok, were not going there'. So right there theyve just lost business from a group of people. But what if that guy would have said 'yea, I been there before, that place rocks'. Well I bet everybody will want to go there.
One thing I try to do is never get close to my management. I would never know if they are doing a good job if I were to be friends with them. It would cloud my judgment. And this is whats happening here. Byt hey, these are just my opinions, and I seem to be pretty succesful.