I heard this advice today. Just be yourself, as if that was sage wisdom that could solve all problems. The person this was told to, stared blankly. I remember being told this when I was young. Just be yourself. The problem is that I had no idea who I was! How can I be myself, when I have no idea who or what that is!
Perhaps myself is not all that great. Perhaps yourself has a few things to learn, overcome, or improve upon. Maybe it should be, be your best potential self instead!