If you need an ally or a favor, never remind them of your past assistance or your moral rightness.
The Core Idea: People are inherently self-absorbed. Reminding them of a favor they owe you will only make them feel guilty and resentful.
The Strategy: Frame your request in a way that shows exactly what they will gain by helping you. When they see a clear benefit for themselves, they will assist you with enthusiasm. #TGIF