I wish there was some easy objective measure of health and energy.
If someone took a sick day for work, they could show by this means that they were truly sick, and not get accused of skipping out on their responsibilities.
And if someone chooses not to do a non-work activity, they could see that they don't have much energy. Then they wouldn't have to berate themselves for their lack of willpower.
And when deciding how to spend our time, we could be like, "Well I've got 10 energy units now. Tomorrow I have to go grocery shopping, and that will require 5 energy units. If I go out tonight, that will use up 7, but if I stay in tonight, I'll build up 5 more energy units. So I'll stay home and rest tonight, then I'll go grocery shopping tomorrow, and then after that, I'll still have 10 left to have fun.