One of my Computer Science modules this year revolved around completing a team project, and one person in the team basically fucked it up for all of us in the last minute.

We had to create a simple task management app for a fictional company, the university did not care about how the program looked and all that mattered was if the app is functional or not. The app relied heavily on a database, so all we basically had to do was get, modify, and add data from a database. Now this person did his part of the programming, but with an outdated database model and did not even test his code as he said MySQL wasn't working on his home computer.

2 days before the final deadline is when we decided to merge everything together in the git repo (as that's when the rest of us finished our tasks), and that's when we found out none of his code worked. We then spent the next 48 hours with little sleep to try our best to fix everything, but unfortunately due to his tasks carrying a majority of the complexity of the program we couldn't fix it all in time and we ended up losing roughly 50% of the marks.

This all probably could have been avoided if one person in the team did look at his git branch properly, but this person was the programming lead of the project and didn't ask for any help at any point until the last moment when we merged everything together. Oh well though, at least I've learnt better for the next team project that I do