These topics (and a few others that have arisen) aren't random stuff, though. They are about things that annoy people on MN. On birthdays (a discussion that ended several days ago, but some people seem determined to drag it back to complain about it), the topic was not birthdays as such, but some MN-ers' criticisms of those who either do or don't want their birthdays acknowledged. On driving, the topic is not driving as such, but the attitude that some MN-ers display to non-drivers.
Just as relevant to the thread as people announcing their name-changes, or calling their friends 'A' and 'B' - neither of which bothers me in the slightest, but obviously are issues to some people.
Probably I shouldn't be entering the debate at all, and thereby no doubt prolonging it- but the 'relevance police' posts are starting to drive me slightly mad in themselves!