There's walls everywhere, a stoppage, a no-go point, a dead end.
Sometimes they're a good thing, sometimes they're not.
My walls are different from yours, but probably not by very much.
I try not to invade yours, because I don't want mine trumpled on either.
My walls protect me, but then keep out other things too.
Things that might be joyous, things I've never experienced, and didn't know I liked.
Walls put up a front that keep others from reaching you, or you reaching them.
They have their walls, you have yours.
Walls keep in everything that we'd like to express, but don't.
Because of walls.