... Yeah. I spent one job emailing code files back and forth (and verbally acquiring locks at the file-level). I spent most of the time there trying to convince

... Yeah. I spent one job emailing code files back and forth (and verbally acquiring locks at the file-level). I spent most of the time there trying to convince the team to at least learn how to use a patch tool and mail patches instead. At another job they just had a shared drive with a single copy of each project and mandated we use a particular editor because it had an in-built locking scheme. There were a few conditions (e.g. crashes) that required manual lock manipulation before you could accomplish anything. People would often manually release locks out of habit, open a file for writing but just leave it open all day in the background while the lock-holder worked, save the old copy when they were closing up at the end of the day, thereby reverting a day's progress. There was no backup strategy in place. This wasn't the 90s or anything, git and GitHub were already established.