Is there a sin in telling oneself that one is beautiful or confident, knowing that subliminal messaging, which relies on a similar idea, is considered unlawful and minor shirk?

We have clarified that subliminal messages and the law of attraction are forbidden due to their violation of Islamic law, and that the least of their evils is minor Shirk (polytheism) by believing in the causality of something that has not been proven by Sharia or by experience. As for a person believing that they are beautiful or self-confident, there is no sin in that, for beauty is relative, and Allah has created everything in the best of forms. However, exaggeration in this may lead to superstitions.