I haven't had a single special moment because I'm still pretty average (or below!) in terms of strength compared to others around here.
My special moments have been more gradual. When I started training I couldn't do a single pullup, or a single dip. I bought a power rack with a cool chinning bar and dip attachment, but couldn't make any use of them in those first few weeks, which was pretty depressing. But I stuck at it and I can now do 11 chins and 15 dips, even do weighted dips which I never thought I'd get to. So when I reflect back, that gives me a bit of satisfaction.