why do we wash bath towles, aren't we clean when we use them

Good question. I changed the title of your post to see how many other "WHYs" we could come up with...

Why do they call it a Firetruck? I already have a fire, I need a water truck!!!

Why would you need a Hot Water Heater - isn't hot water already heated?

How can there be self-help “groups?”

What happens if you wear an 18 hour bra for 19 hours?

why do people call them ATM machines?

I begin to feel confinded. 

after eating do frogs have to wait an hour before swimming?

Can fat people go "skinny dipping"?

Now why do they call them 24-hour contacts if you only use them for 18-19 hours?

Why do they put up Deer Crossing signs if the deer cant read them and know they need to cross near it?

Who would have guessed a sign was needed to tell you if it is raining the road might be wet....

If olive oil comes from olives
Peanut oil comes from peanuts,
palm oil comes from palms,

Where does baby oil come from ?

Why do they sterilize needles for lethal injections?

They put up a "No Smoking" sign at the front door to our business. And on it was the "no smoking" supposedly done in Braille. How would a blind person know that the sign is there in order to read it?

no cell phone use in school zone signs are all over, 200 dollar fine they say, does that count for the students and teachers on campus in the school zone too?

Who was the first person to look at a cow and say"I'm gonna squeeze these dangly things here and drink what comes out"?

Shouldnt Ronald mcDonald be like...Heavier?

Can a person be a closet claustrophobic?

Why is the word for fear of long words so long"hippopotomonstrosesquipedaliophobia"?

What was the greatest thing before sliced bread?