Dog chain on street

You know.

There was a dog on the streets.

Most of the time the dog is very quiet.

But one day the dog got chain up on the outside of the gate.

When I walk past the street.

The dog barked at me.

Like I did something to him.

I wonder why he barks at me.

Was it because.

He was protecting his home.

Or did he see me as having more freedom than him?