Aside from simple programs I wrote by hand-transcribing code from the "Basic Training" section of 3-2-1 Contact magazine when I was a kid in the '80s, I would say the first project I ever undertook on my own that had a meaningful impact on others was when I joined a code migration team when I was 25. It was 2003.

We had a simple migration log that we would need to fill out when we performed any work. It was a spreadsheet, and because Excel is a festering chunk of infected cat shit, the network-shared file would more often than not be locked by the last person to have the file open. One night after getting prompted to open the document read-only again, I decided I'd had it.

I went to a used computer store and paid $75 out of pocket for an old beater, brought it back to the office, hooked it to the network, installed Lunar Linux on it, and built a simple web-based logging application that used a bash-generated flat file backend. Two days later, I had it working well enough to show it to the team, and they unanimously agreed to switch to it, rather than continue to shove Excel's jagged metal dick up our asses.

My boss asked me where I was hosting it, as such an application in company space would have certainly required his approval to procure. I showed him the completely unauthorized Linux machine(remember, this was 2003, when fortune 500 corporations, such as my employer, believed Ballmer's FUD-spew about Linux being a "virus" was real and not nonsense at all), and he didn't even hesitate to back me up and promise to tell the network security gestapo to fuck off if they ever came knocking. They never did.

I was later informed that the team continued to use the application for about five years after I left.