It's rude to not share something someone helped you get.
Arnie bought Tom a vacuum for Xmas last year, and now Arnie wants to borrow that vacuum.
Tom needs to decide to lend Arnie the vacuum or not.
Tom allows Arnie to borrow the vacuum because Tom trusts Arnie with it.
Tom doesn't lend the vacuum to Arnie, since if Arnie accidently broke it Tom would have no way to get another.
Arnie thanks Tom for lending it to him and Arnie quickly vacuums his house.
Arnie has feelings of resentment and anger directed towards Tom.