My recent gripe is that I've used Linux for more than half my life and I'm well into my 30's. I feel like my ability to navigate a system has gone _backwards_, Debian no longer accepts 'init 0' as a command, ipconfig isn't a command anymore, systemd changed the whole subsystem from underneath me, ubuntu/snap decided not only to litter+bloat my filesystem with needless duplicates but also that not only would I prefer…
For me, I can't see how anybody actually used/managed linux systems before they standardized the api for creating/managing daemons. A simple convenient api layer for saying to a machine "I want this program running always."