8. Dr. Manhattan Was Responsible For The New 52
Within the depths of comic fandom, there had long existed a theory that the main DC universe and Watchmen universe were intertwined. As such, when the first DC reboot - the New 52 - came out, this speculation naturally turned into a theory that Doctor Manhattan had been the one to initiate the universe's restart, changing DC's history behind the scenes.
The weirdest thing about this theory is that it actually turned out to be right, as Doomsday Clock canonically shows that Manhattan had in fact been messing with the universe's timeline, proving every moment of wild fan conjecture to have been correct the whole time.
While this news was poison to anyone who shared Moore's view that Watchmen should be kept separate from the main DC universe, it did provide a legitimately interesting way to retroactively explain the company's reboots. It was also especially potent in alleviating some of the flack DC had received for having both the New 52 and Rebirth events restart the franchise twice in the span of a mere decade - although given the mixed fan response to Manhattan's appearance, it's unclear if this explanation fully 'fixed' many of the issues people had with these events.