People should be friendly with their neighbors.
Nick has a lawn mower and his neighbor wants to borrow the mower for a price.
Nick wants to let him borrow the mower.
Nick lets his neighbor use the mower for free.
Nick agrees and charges his neighbor $15/hr to use the mower.
Nick's neighbor lets Nick borrow things for free in return.
Nick's neighbor feels ripped-off and never invites Nick for events.