https://www.neelnanda.io/blog/38-slack
As Neel Nanda puts it, slack is “spare capacity”. It’s having the room to be able to do what you want and cultivate intrinsic motivation.
Not being pushed to my limits. Having downtime and room to explore. Being robust to small risks. Not feeling constantly stressed and anxious, having things weighing on my mind.
Slack’s almost necessary to have a fulfilling, exciting, and fun life. By default, most people tend to spend their slack, so it’s important to intentionally preserve your slack. Many of the components that help you build towards a life with high slack are things that can’t be as easily measured (stress, focused attention, sleep quality, fun) as the things we tend to trade our slack for (time spent working, money). The only way to create more room for slack is to trade other important things for it. (You can’t do everything).
Slack encourages whimsy, which is the state of mind that leads towards doing what’s excitingly ambitious.
I call this state of mind whimsy - being in touch with my emotions and my whims, in touch with what I really care [about], and following those where they lead.