Doomed to meet again at rock bottom
Bill can kil somebody with a crayon if he tries hard enough
Just to be clear. Neither Bill or Steve recall their first encounter, nor do they know their parents knew each other at some point.
It's one of those things where fate would've had them meet one way or another
Fun fact, their parent's didn't realize the other couple passing by because their eyes are pointing at their respective partners, and they were distracted with their own matters. (this representation of Euclidea is inaccurate, things are still flat, but that wouldn't be too fun to draw)
But if the kids hadn't let go so easily, the parents would've noticed each other and established a good friendship, relating on how their kids are more similar than they first though, causing a butterfly effect, making Euclid approve the loan faster, Steve's parents to move sooner, saving them, having Acute continue to be Bill's doctor and never approving the blinding treatment, and Bill and Steve becoming good friends, preventing Bill form feeling excluded and misunderstood.
Bill then never destroyes Euclidea.
Alas, they let go and went different ways.
Next time they held hands, fate would make sure it's impossible they separate again.