You would think it would still be common I mean we are all good solid, human beings right?  Well of course we are, except from time to time we just do not act like it.  Call it whatever you want;

The Golden rule; treat others the way you want to be treated

I’ve also heard of the

Platinum rule; Treat others the way they want to be treated

Either way just be nice.

Share good feedback as often or preferably more often than you provide bad.

If someone just did something good for you, let them know.  If they could have done better it is ok to let them know in a nice way.  Then again if someone just spent a bunch of time to help you  show some appreciation.

Losing customers is unfortunately a part of business.  It is almost inevitable and sometimes preventable.  Bottom line is there is a nice way to leave, no sense in burning a bridge you may need to walk back over some day.