Humans convert the sun's energy into physical, emotional, mental, and spiritual energy to share with other humans but often expect something in return. Where did we get the energy to create 'expectation of return'? The sun expects nothing in return for its energy.
Thankfully, in the best cases of the return, we expect to experience reciprocity or mutual benefit. In the worst cases of return, we expect everything and are downright selfish or even criminal. The sun's energy ultimately fuels both.
Perhaps there's a clue in the fact that sun exposure at either extreme is deadly.
Too much sun burns. Too little sun kills. The sun expects to be consumed in moderation.
Human expectations are a bit like that, expecting too much, or expecting too little of oneself or others is not the best use of human energy.