The praise of the envious is far less creditable than their censure; they praise only that which they can surpass, but that which surpasses them they censure.

Praise from someone competing with you carries information, and not always the information it appears to. When a rival compliments your work, it often means they consider it within their reach; when they find fault, it may mean the opposite. Applied mechanically this goes wrong, and plenty of praise is simply sincere. But it does mean a rival’s approval is a poor measure of whether something is good.

Notice whose opinion you are actually working for. If it belongs to somebody who would find it hard to praise you generously, you have chosen a judge who cannot give you a fair reading.