One; Correct posture does not mean that the body will feel comfortable.
I believe everyone has a correct understanding of this sentence. Straightening your back can really keep your figure, physique and bones in a correct posture, but this posture will make us feel tired. Because this posture will make muscles tense, bones will certainly make us feel uncomfortable when we are working all the time, but it is precisely because of this discomfort that we can shape our bodies and make our bones grow healthier. In other words, the purpose of this correct understanding is to correct some bad behaviors, not to make us feel comfortable.
Second; Muscles have memories and need to relax.
I want to explain to you once again that our muscles have their own memories. When we stand up straight and nervous, we will always remember this feeling. Naturally, it will make our muscles more tense and protect our bones, but long-term muscle tension will make us more and more tired, because we always make our muscles tense and there is no way to relax, which is the biggest reason for feeling tired.
In a word, if we want to have a good body, a strong figure and keep our body and bones in a perfect and healthy state all the time, then we must endure some physical discomfort, because this is a necessary condition for us to want a correct and enviable figure.