for my last university-level but pre-university computing science course, I needed to do a project (taking up about 1/2 of the year) to demonstrate what we learned in the course. traditionally people selected to make a quiz using VB6. however, past me was overly ambitious and instead of choosing the obvious, I instead decided to build an electronic device that could load quiz files from json and an editor that would allow you to create your own quizzes for the device.
so I spent far too long designing the circuit and choosing all the components. the device had a nokia 3310 screen, gameboy-style button layout, programmer interface, micro usb, avr microcontroller, lithium polymer battery charger/controller, buzzer, status leds... all kinds of over-the-top features. spent around 150 pounds on components and the circuit board, and many hours of my free/study time (luckily I had fewer subjects that year).
components arrived and I got to soldering everything together. first things first, one of the components got really hot and started smoking, iirc it was the buck boost converter. couldn't get anything to work, I think the only thing that did was the battery part of the circuit.
so I had to pivot, changed my entire quiz creator software to remove any features related to device programming, and hurriedly wrote a javascript web-based quiz player that worked with the json files that the creator output. after thorough testing and finishing the project report and documentation (meticulously detailing every test procedure, project requirements etc. and totaling 17k words) I submitted the project.
few months later, I find that I got a C in the course.
there are still remains of this project on my github..