You're expected to help people when they need it.
Steven's house had a tree fall down on the roof, and he knows his friend Anthony is talented carpenter.
Steven needs help fixing his house.
Steven ask Anthony for help, and Anthony is willing to help his buddy.
Steven calls Anthony up on the phone and asks for help with his roof, and Anthony gives him a price quote.
Steven feels very happy that his friend is so willing to help.
Steven feels betrayed that Anthony won't help him for free.