There is perhaps no other Drupal-related issue which commands so much attention from site admins, Drupal developers, and Drupal core alike, as the subject of Drupal updates/upgrades.
The Players
Site admins typically want to have the 'latest and greatest' version just for general purposes. This is, of course, very understandable, all other things being equal.
Drupal developers like to be able to keep up with the latest release for various reasons: a) to take advantage of new features, b) to keep their skills current, b) because their clients want it, c) as any bonafide geek knows, it's alway fun to check out the new toys.
Drupal core is always concerned about Drupal updates, well because...it's Drupal core. The project and Drupal itself is dead, or at least frozen in time, if it ceases to innovate at semi-consistent intervals.
Utopia
In a perfect world everyone - site admins, Drupal devs, and Drupal core are always perfectly in sync - all the time, 24/7.
Reality
Keeping up with the current version of Drupal core is not always practical. In some cases it might even be downright detrimental! This statement applies particularly to start-up sites, and/or people who are short on time. But you know what...
...IT'S OK!
