Can I take this guys bucket at a construction site?
Why are you stealing a bucket?
He left it there, can I keep it?
It's wrong to take someone's property without permission. You should leave the bucket alone.
It's not like he cares about it. Also, I'll give it back later.
You wouldn't want anything of yours to be stolen, would you? So don't steal from others. It is a horrible thing to do, and people will believe you're a thief whether you return it later or not.