I wear MU because I look so much better for it. It makes me feel happier with my looks eg I have big eyes which I love to play up but thinnish lips which I can make look plumper with VERY careful application of lip liner and gloss. I am also very pale and look washed out unless I have foundation (which covers my red blotches too) and some blush and bronzer. I catch myself in shop windows when I'm not wearing anything and hate what I see. With MU I can change that to a degree and feel a lot more confident.
I LOVE make up for so many reasons( I get a real high when I enter one of the big Sephoras or a MAC shop) I think that properly applied make up makes most girls feel happier with their looks.
In the past I have been a Professional MA but had to give it up due to a serious spinal injury. However, I have just applied to work with a charity called "Look Good, Feel Better" I'll be doing an afternoon session every two months or so with female Cancer Patients to help with their self esteem after losing their hair and the toll the medical treatments take on the way they look. It has been proven to help women who have been unlucky enough to have contracted this terrible disease, to feel more positive about themselves. I think that says a lot about the "power " of make up to all women.