I accidentally overwrote /etc/passwd once and I allowed /boot to run out of space during a kernal update and I created a local user with the same user that was also on the realm/domain that I had joined and various bash script issues.
Some stuff I've had to fix that someone else did:

• named a file rm -rf
• rm -rf /bin instead of ./bin -- Also the fact that they had sudo was crazy and also I guess this was the second time
• chmod -R 777 /
• Various software bugs running swap out of space or hitting the inode limit by creating files over and over again with a timestamp in the filename and having to remove all of them because there was no backup to the OS
• Someone disabled SELinux because something wasn't working but didn't tell anyone -- ugh
• Compiled java because they googled some issue and followed some old tutorial without understanding anything instead of using alternatives and symlinked the old java from /bin to /home/theiruser/java -- had sudo because he was a Windows domain admin.
• Cybersecurity guy didn't know what some VMs did so he turned them off and figured he'd find out if/when someone complained. Caused a massive core services outage.
• Same Cybersecurity guy deleted a bunch of data because he wanted to see how the sysadmins would respond and witness backup restorations. He did not inform anyone.
• Cybersecurity guy above still has Domain Admin and sudo everywhere. I would have personally removed his privileged access regardless of what 'CyberSecurity' management thought but I was leaving for a new job by then anyway so I figured I'd just let them eventually lie in the bed they made.

There's more but I don't want to keep going because it is Sunday and I don't want to ruin it.