Statistics: I couldn't cope with online homework.
"Cyber security": I just gave up on a lot of stuff that semester for various reasons. That class was annoying, we were the best team in capture the flag but I got tired of trying to fit 6 Ubuntu VMs on my ancient thinkpad just to run someone's crappy PHP wrapper for nmap so I could do the fill-in-the-blank assignments.
web dev: The professor marked all my assignments I didn't turn in as 100% so I thought I was fine and then on the last day of the semester told me I'd need to turn them all in or get a "NP" or so for the class.
I failed the "can you use Microsoft office" exam they gave us at the beginning because I never use office. That pissed me off quite a bit.
I nearly failed some music appreciation class because I just didn't feel like turning in the essay at the end. The professor was extremely nice and let me email it to him like two months after the semester ended.
I actually finished my degree, have a good job, a 401k, a girlfriend, and a boat now.