There are behaviors we stopped doing because of speciation. For each of those behaviors, there is a day in history in which one of our ancestors did it for the very last time.
In other words, there's going to have been a moment where the last proto-human to do it hung off a tree branch with their feet for the very last time in the entire evolutionary branch that would eventually become us.
there's a forgotten chatroom somewhere out there, where you and your mates from middle school used to spend time on. at some point someone will send the last message, not even knowing it was the last one
Yes :) this is what I mean. And we can go further back in time, beyond proto-humans. Our ancestry includes mammals, reptiles... all the way to single cells.