I have five up and running, mostly 3 or 3Bs, plus the original RP 1 that I bought years ago but never hooked up...
I think the most important moment was when Linus "accidentally" lost his Minux partition and decided then to stick with Linux, as outlined in his book "Just for Fun: The Story of an Accidental Revolutionary": "...I mistakenly auto-dialed my hard disk instead of my modem. I was trying to auto-dial /dev/ttyl, which is the serial line. But by mistake I auto-dialed /dev/hdal, which is the hard disk device. The end result was that I inadvertently overwrote some of the most critical parts of the of the partition where I had Minix. Yes, that meant I couldn't boot Minix anymore. "
If he still had Minix he might have gotten bored with Linux and had given up on the development, but instead he had to make a decision to go "full Linux".
If not for this accident, we might not have Linux today.