There are some people that will always point out your faults with no intention of making you better. They will be there to tell you that you are wrong, or not good enough. Or will never be better than them. How they could have done things better or differently. There are people that want to see you fail.
One of the best things you can learn is to recognize those people for what they are and then ignore those people. Seek out people who make you better. Who want you to be successful. You can do it all by yourself, but success is easier and more rewarding with a team.