So let's say you wear the mask in public, and it actually does catch the germs of a person coughing there.

The germs are now ON THE MASK. So what, you keep wearing it, breathing through it, touching it, and dragging any germs on it everywhere you go?

And it's not like there's only one germ in the world. I know the media is making it SEEM that way, but believe it or not all the other old viruses and bacteria are still out there. Bacteria particularly will begin to accumulate and grow in the warm humid environment you've strapped to your face.

There's a reason real healthcare professionals wear disposable masks and they don't keep the same one on between patients to prevent potential contamination. A thin bit of t-shirt fabric you wear all over town all day long is probably doing you more harm than good.