Same. Those scenarios point to more of a "meaning of life" and "reason behind it all" types of scenarios, assuming that the message-deliverer is trustworthy/ accurate. Knowing such weighty matters might heavily shift the way you live, the choices you make, and the things you invest your energy and time into.

The universe's deepest darkest secret just sounds interesting and I must already be living with the consequences of it in some way.

I think a more localized version (your spouse or family's darkest secret) might be a more difficult decision.