Earlier this year I noticed that Bash released version 5 . Now Linux turns 5 as well. While Linus did say "that '5.0' doesn't mean anything more than that the 4.x numbers started getting big enough that I ran out of fingers and toes," it's still a round number and makes me think back about the various version numbers of the kernel that I've used over the years.
It also makes me think about version number inflation. My relationships with Bash and Linux are approaching drinking age in length. Chrome, having only been around a decade is already at version 72.