I kept a daily blog at a company I was at - I kept all my notes in there about what was said at meetings, why certain code was done certain ways, etc - far more

I kept a daily blog at a company I was at - I kept all my notes in there about what was said at meetings, why certain code was done certain ways, etc - far more than you could put in a commit message, for example. I got (a bit) laughed at by teammates. After I left, one thanked me because it was a huge help for trawling through the mess of stuff I left behind (which I'd inherited from someone else in an undocumented state). Did I leave it in a perfect state? Of course not, but all the external factors that played in to why things were done certain ways was searchable (meeting notes, pointers to tech articles, bug reports, etc).