I just remembered the first time I set up a Linux-Server. It was a simple Apache webserver at my first internship anf I didnt have a clue about literally anything.

My mentor guided me through and gave me literal step-by-step instructions (alright, now type... and now type...).

At the end he told me "OK, now run 'sudo rm -rf /*' to finish setting up". Me, being the naive and clueless motherfucker I am, happily nuked the everloving shit out of my newly setup server. I was like "Alright, WTF just happened??" He then told me "Now that you know how it works, do the entire thing again all by yourself. And you just learned an important lesson: NEVER exexute commands you dont know what theyre doing". I really did learn a lot on that day and still follow that lesson :D