I love seeing screenshots of alpha Minecraft, those times coincided with what I'd say were the happiest days of my life. Had just reached adulthood, was almost done with high school, recently made friends for the first time, finally had money, could afford to replace my toaster from 1998, and overall felt hopeful for once.
First pic is the only alpha screencap I have left. I thought I took one from this old /v/ server, but I guess I lost it. It was a cool picture. We found a really interesting mound with a big hole through it and made a watchtower out of it. I remember us also using a server mod called "Runecraft" that let us cast spells by placing multiblock structures.
I also have a map of a server Tohno-chan used to have, one of the comfiest servers I've played on. Especially with the Painterly Pack loaded.