There are 2.5 billion seconds in a lifetime and (as of December 2018) 7.7 billion humans on the planet.
If you fight evil one-on-one, if you refuse to pick your battles, if only 1% of humans are sociopaths, you’ve got 21 waking seconds per opponent — and you’ll be fighting your whole life, from infancy to your dying breath and from when you wake to when you sleep, with no holiday, no weekends, no retirement.
Conversely, if you are a product designer, and five million people use your stuff once per day, every second you save them saves a waking lifetime of waiting per year. If you can relieve a hundred thousand people of just 5 minutes anxiety each day (say, about social media notifications), you’re saving six and a half waking lifetimes of anxiety every year.
When people complained about the cost of the Apollo programs, someone said Americans spent more on haircuts in the same time. How many Apollo programs of joy are wasted tapping on small red dots or waiting for them?