sweat the small stuff

From the combination, possibly boosted by its alliterativeness, of sweat in its colloquial sense meaning to worry, and small stuff designating petty issues.

sweat the small stuff

1. (idiomatic) To worry about petty issues or insignificant matters.
   • 2017 April 20, Tim Urban, “Neuralink and the Brain’s Magical Future”, in Wait But Why‎, retrieved 2017-04-21:

     The prefrontal cortex is the other character in those internal battles that go on in your life. [...] The higher being who wishes you’d stop sweating the small stuff.

• don't sweat the small stuff