Something I learned awhile ago is that most people that I consider "celebrities" really aren't that famous, and as such are generally pretty happy to respond to emails.

In ~2014 I sent an email to Joe Armstrong (one of the creators of Erlang) asking some questions about concurrency because I still didn't fully understand why Erlang was supposed to be better for it. I expected him to just point me to an FAQ or simply not respond [1], but instead he wrote a very long, detailed explanation about the rationale of Erlang's design. It was well-written and it made a lot of things "click" in my brain.

That simple act by Joe was extremely instrumental in my career, I think for the better. I became very interested in Erlang, but also just concurrency theory and distributed systems, and I would like to think I almost understand it now :)

He and I would exchange emails occasionally over the next few years and he seemed genuinely enthusiastic about programming, Erlang, and people using it, and despite me barely knowing the guy, I was genuinely pretty sad when he passed away in 2019.

I think about that a lot; if I hadn't sent a dumb cold email my entire life would likely be very different.

[1] Which, to be clear, would have been perfectly fine!