Strength to walk

How can some not have the strength to walk as a form of exercise when everyone already walks every day?

Free walking

If walking is the best exercise and free, how come they keep making exercise machines?

Sidewalks

How come some streets don't have a sidewalk? Where are you supposed to walk then?

Rain

Why worry so much in the rain that your hair gets wet? I'm more worried someone won't see me crossing the street.

Three out in street

People who walk three out in the street even while cars are coming down. Isn't that dangerous?