Generally speaking, when I criticize someone’s workers, the normal response from the manager is to defend the worker.
Gee, we never had a problem before (B.S.)
Hmmm, this is the first time that happened (Yeah, right)
Maybe you are the one at fault for not giving clear instructions (I have it in writing, do you want to read it?)
I have heard every excuse for defending mediocre workers. Honestly, nobody is perfect and we should not expect people to be. However, my rule of thumb is as follows.
If you side with your worker and against your customer — you will have more workers
But, with more workers and less clients, you will have no way to pay those workers, then you will eventually lose the workers, and then you won’t have a business if this pattern continues.
If you side with your client against your worker — you will have more clients.
You might lose a mediocre worker here or there, but mediocre people are replaceable. Just make sure you don’t lose your star employees or you will really be up a creek.
In real life your job is to please everyone. But, try to be fair with your clients. If they have a legitimate gripe, or you are not sure who is right, try to validate their point of view — if you want to keep them.