We think that we have helped some man and expect him to thank us, and because he does not, unhappiness comes to us. Why should we expect anything in return for what we do? Be grateful to the man you help, think of him as God.
Is it not a great privilege to be allowed to worship God by helping our fellow men?
If we were really unattached, we should escape all this pain of vain expectation, and could cheerfully do good work in the world.
Unhappiness or misery will never come, if work is done without attachment. The world will go on with its happiness and misery through eternity if we work without attachment and expectations.
— Swami Vivekananda