It shouldn’t happen but it does.
And the truth is everyone’s fallible and because of that there is no use complaining. I think critical thinking is very important and can be confused with criticism in a judgmental way which should be avoided, but analyzing a performance to discover how you can better your own is worth it’s weight in gold and needs to be the general course of action.
So don’t be fooled because when people complain their views are usually subjective and could lead them to say something that one day could actually be said back to them as well.