Why do people wear sunglasses indoor?

I notice on occasion you will see some wanker wearing sunglasses indoor. Why is that, I noticed women especially do this with big dark tinted bug eyed large sunglasses.

Is it to conceal drug use?

 

As I recall the invisible man use to wear them indoors.

 

Once indoors, they become fashion shades, not sunglasses

 

Because Billy Gibbons does ...man!

 

http://www.youtube.com/watch?v=A9p0Ac5bLlI

When I saw that video I was like, what? Those are my sunglasses exactly!!

 

Billy is probably the Kewlest person alive on planet Earth.

 

And that tone he gets ...squank ...squank ...whistle! Love it.

 

http://www.youtube.com/watch?v=G5MteZqXl20&feature=related

 

Could be that they are trying to avoid seeing to much of the surrounding ugliness.

 

maybe its just