inverted U's
In scientific research, there is a concept called the inverted U curve, which appears when graphing the amount of activity vs. well-being. In this graph, well-being increases and eventually peaks before decreasing.

In my mind, this is the scientific version of "everything in moderation. " It's how I think about my relations with all types of activity. There is an ideal amount beyond which we do ourselves more harm than good.
An unfortunate limitation of a graph is its static nature. The inverted U graph pictured above will look the same regardless of what day you view it. But our real-life inverted U's are constantly shifting on macro and micro scales.
Many obtain a seemingly limitless social battery in some life periods, perhaps during childhood or high school, but later find a hunger for solitude and peace. The micro-shifts are more transient, such as when you wake up craving quiet time after attending a social gathering the night before. It's okay either way.
I've often gotten frustrated trying to force my inverted U's to behave according to some fictional ideal that I either invented or that society burned into me. Listening to what your inverted U's tell you is the right amount today or at this stage in your life is essential.
This truth reminds me of my changing relationship with writing music, which I've noticed over the past couple of months. I used to be militant about writing for X hours every day, and that habit was highly joyous.
But recently, I have found myself spending more time reading or doing other activities. At first, my brain said that's bad because now we're doing less music, and that's not ideal: Look at how wonderful life was when you were clocking in many more hours of writing! Surely life can't be as good with less!
I now realize that my musical inverted U shifted, as must I. The spark to write heavily again will return in full force, and until then, I'll stick with my more limited approach. When it does circle back, I'll understand why it has and not resist reality (as I did when it left the dock).
This concept of unconditional openness to the present moment (regardless of its objective content) is at the core of many religions (Buddhism, Hinduism), philosophies (Stoicism), and spiritual practices (Taoism). It's wild that such diverse groups of people, spanning thousands of years, often arrive at the same truth: letting go and flowing with the river is our very nature.