Learning how Systemd manages the network was a total mindfuck. There are so many alternatives, all of them being used differently by different tools, partially supported. networkd, Network Manager... There were other tools, they shared similar files but had them in different /etc or /usr folders. There were unexpected interactions between the tools... Oh man, it was so bad. I was very disappointed.

I was really into learning how things really worked in Linux and this was a slap to my face because my mindset was "Linux is so straightforward". No, it is not, it is actually a mess like most systems. I know this isn't a "Linux" issue, I'm just ranting about this specific ecosystem.