It's not a huge annoyance but one area of chaos in Linux that can show the 'too many cooks' problem is /etc conf entries. Debian/Ubuntu's for Mariadb is really quite confusing if you've been away from it for a while.
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...Also if you do experiment with firewalld, think really carefully about your Zones. It's really easy to have to start over because you can't duplicate subnet entries; this can be trickier than it sounds. Sure you can write rich rules but then you might as well stick with iptables.
