Advising a person to be himself /herself is not a bad advice at all. This is because being one's self makes life easier. When you try to be someone else, it's takes away the essence of you being created. Ever sat down to wonder why no two persons on earth have the same finger prints? It didn't just come to be. It was made that way purposefully because we were made uniquely. Also, being you is the best thing you can be. No one can do you better than you.