Honestly? To my mind, the answer is "Not much". And pretty much zero of that involves my work in tech, as much as I hate to admit it.<p>Probably the biggest thing I've done in my life that truly "mattered" was the time I spent volunteering as a firefighter. During that time I was never involved in any dramatic, news-reel-worthy rescues or anything, but there were some times that our presence made a difference in terms of saving someone's home from burning down or whatever. And we probably helped save a life or two, with some of the vehicle extrications and other non-fire calls we were at.<p>One call in particular stands out in my memory, but let me give you some background info first. With pure volunteer fire departments, its often quite difficult to get a "quick stop" on a structure fire and keep the fire to "room and contents". Quite often on structure fires in rural areas, the home is damaged beyond repair, if not burned "to the dirt" as they say. The reasons are multiple, but a lot of it reduces to response time (from dispatch to "on scene") due to travel distances + the time it takes volunteers to respond to the station from wherever they are. This is especially pronounced in the daytime hours when volunteers are more likely to be at work, or further away for various reasons.<p>So one day I was at our (Supply VFD) station during the day, just hanging out. I think I was working a night job at the time. Or maybe I just had the day off, I don't remember now. Anyway, I'm at the station and we get paged out along with Bolivia VFD and Winnabow VFD for a structure fire in Bolivia's district (but near the line between their district and ours). I radio in to dispatch to say our engine is standing by waiting for a crew. By happenstance a member from another neighboring department was driving by and was more or less right in front of our station. We were old friends as I'd formerly been with that department, so he radios me and asks if I want him to come roll with me. I tell him yes and a minute or two later we're en-route. We're already way ahead of the normal VFD response curve at this point, and we wind up being the first arriving engine. Bolivia's chief was on scene via personal vehicle, and he and I took a 1-3/4" attack line in and knocked down the fire, while my friend from the other department ran the pump. The fire had started in the kitchen, probably on the stove-top, and we managed to contain it to the kitchen and save the structure to the point that the family was able to have the damage repaired and keep living there.<p>That didn't happen a lot for the response time reasons mentioned above, plus water supply issues and other factors that make firefighting difficult in rural areas. Most of the time we wound up focusing on protecting exposures more than "saving" the original fire building.<p>So yeah, small thing in the grand scope of things. But to the family that lived in that house, our actions that day "mattered". It's one of the few times in my life I can look back and see that very clear, direct line between my participation in something and an outcome that mattered to somebody.