We've learned that Hatha Yoga or Union through Effort focuses on cleansing the physical body first. Unlike the practice of Raja Yoga which focuses upon the Yamas & Niyamas as the beginning of our practice, Hatha Yoga focuses on controlling the body.
If we can understand how our body works, then not only can we control it but we can respect it. Cleansing isn't necessarily about using a neti or swallowing a milk-soaked rag. It's about thinking about what you're putting into your body, how you use your body and what you do to your body. When we understand our bodies, we understand ourselves and we are better able to look upon ourselves with honesty.
Have you ever viewed yourself with honesty? Without denying the aspects that you dislike or fear to admit to? The saying "you can't make others happy unless you are happy yourself" is about how you view yourself not about how much money you make, the car you drive or the clothes you wear. Know yourself and you'll learn that these things are not you. Know your body and you will find out who you really are.