If you don't want uninvited guests moving in with their entire stock and barrel, you need me to keep them out.

You think you've got it bad? People use me as a milestone for ugliness. In fairy tales, I'm usually some kind of curse or punishment or bad character. In a book about kid wizards, I'm the least-wanted pet. Even nature mocks me by creating a stool in my honor... that I'm too big to sit on!

I can lock your door or dash down the street. One holds things shut, the other moves feet.

A music group that performed an amazing cover of Stairway to Heaven A pump so efficient that everyone has one The edible inner core of certain trees

You take me to go everywhere, I can be made of cobblestone, dirt, brick, concrete or paved. Or I can be less concrete and more cinematic, but lead to redemption or perhaps El Dorado.