It's easy for me to *not* talk about life-quality improvers like clang-format, since (1) your mileage may vary, and (2) there are SO MANY ways to improve life that you've probably just improved your life and want to tell ME about yours.
That said, clang-format gives a very nice quality-of-life improvement.
Also, Japanese-style #bidet. My whole family agrees: bidets are huge quality-of-life improvement. Typesetting your code by hand is only slightly more barbaric than manually wiping your butt.