Function: nothing rotates at zero clearance. The engineer's tolerance, the typographer's optical correction, the animator's added noise, the therapist's "good enough": every discipline that makes working things has independently discovered that a few micrometers of looseness is not a defect. It is the operating condition of anything that runs. Your routines, your frameworks, your self-optimization: all real machinery, and all of it needs the gap.
Tension: too much clearance and nothing transmits; the shaft rattles in the race and the machine shakes itself apart. All play and no structure is not freedom, it is noise. The spec zone in the middle, snug enough to transmit and loose enough to move, is where this whole blog lives.
1,000 true readers, no funnels. One mechanism, one honest scar, one thing you can run this week.