The cause of acne? What is it?
Is it stress? Is stress causing all that puss on my face, chest, back and arms?
I don't understand, I'm am sure that I am not the most stressed out person in the world, in fact, everybody experiences stress (yeah, that's probably why everybody who has Acne or any other problem tends to blame stress, because stress is COMMON).
Am I going to cure all the puss all over my body if I start laughing like an idiot all the time for no reason? YES!!!!!!!!

Rewind that, NO!

Here is what I think of acne. Why is Acne only on the face? The most Acne people have is on their FACE usually, then following the back, chest and arms (or penis for some of you). Why is there no acne on my feet or hands (no hairprone area's there or connective hair prone areas).

Every think that your hair oils are causing acne? The oil in your hair? Because I've known some people who had no hair, who decided to get a long hair style and developed acne.
Want to know what it is? Hot water, natural oil and shampoo/conditioner = acne.
When I had oily skin, I would develop acne. So would a few other people for the first time of their lives when they got longer hair. The medical theory on acne is "sebum" (oily skin... although there are people with oily skin who don't have acne).

How some people avoid acne? Daily avoiding oil on their face. Not using shampoo/conditioner. Taking cold showers. Not washing themselves at all. And by last, a strong immune system to block the puss developing.