I am feeling homesick. 😢😢😢😢

Question: What was the worst mistake you made in Linux?

So... Because I've finally upgraded my PC (rip money on bank account) I can now run a VM with Linux all the time that isn't slow as a snail.
I installed Linux mint, with 4Gb of Ram and 6 cores, and it runs like a brize, while I play on windows and stuff. BTW I'll be using the VM for programming stuff, since I'm finally at home (homesick because of burn out), when I'm better I'll finally have the patience and memory to learn new stuff and get my projects up and going.
And because I've never really used Linux I'm watching YouTube videos about Linux, and found a Perl I've watched before, #Linux Sucks
And It's great... I get so many laughs, but also, learn stuff I didn't know, like, how Linux Pros make mistakes that Windows users can't even do, like breaking the OS.
So... I would love to know, what was the worst mistakes you ever done on Linux? How did you brake you're system?
BTW this would also be great for noobs like me to not make them... I hope. Since I'll be moving full Linux when I'm comfortable.

BTW @dfox this would be a great wk ...

Git repositories? What is the best online for free

Android Studio + Kotlin

Hey guys
So, I'm thinking on starting programming again... slowly cause of Burn out

I'll be homesick now for a while and I want to start coding again.
I've been making Apps for Android in App Inventor, but now I want to make stuff that sincerely will be hard on a complete visual programming language.
So, I'll be starting to learn kotlin

My problem now is that I don't do any really programming for years, and most of my knowledge is from 1990's. I want to put my code in a git repository but GitHub doesn't have a free option and I can't spend money now, since I'll gain a lot less.

What are the best alternatives online, or tricks, like online VMs

thanks for the time

Have to translate an API library from Ruby into PHP for work, and I swear it's all of the worst pieces of BASIC and Swift thrown together. To top it off, looking up a symbol chart for it to try and get a handle on the symbols they love to throw in front of variable and method names is useless because "symbol" is a freaking type in this language! Arrays are apparently called "hashes" now, and I can't quite tell if modules are supposed to be namespaces or classes yet...

If Ruby has redeeming qualities, I'm definitely open to hearing them. Right now I'm kind of feeling homesick for vanilla C, however...