The problem is that some people that call themselves “Professionals” post sub-par work and cry about it when someone says it’s bad. What’s really bad is the fact that you charged someone good money for bad work. If I went into a restaurant and ordered a steak and got ground chuck, I would be pissed and damn straight I would tell them about it.
The thing to remember is even professional photographers make mistakes and take bad photos from time to time. The difference between a professional and a faux-fessional is that the professional does not let anyone see the bad photos, they never see the light of day. Only put your best work out there, that’s the way to being pro. If your work is not good enough, then do something else.
Whether you are just starting out or a “Pro” be a sponge and absorb the knowledge that you can gain from others, that and practice, practice, practice. That is the way you get better. Hell, I practiced on a beauticians modeling head when a didn’t have anyone to help out, and I still have it.