A passage from Marcus Aurelius
Marcus Aurelius, Meditations 5.6
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One kind of man, when he has done a service to another, is ready to set down the favour to his account. Another is not ready to do this, but still in his own mind he thinks of the man as his debtor... But a third in a manner does not even know what he has done, but he is like a vine which has produced grapes.
Related passages
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Begin the morning by saying to thyself, I shall meet with the busy-body, the ungrateful, arrogant, deceitful, envious, unsocial.
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At dawn, when you have trouble getting out of bed, tell yourself: 'I have to go to work — as a human being.'
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Take care not to be Caesarified, or dyed with purple; for it does happen. Keep thyself then simple, good, pure, serious, free from affectation.