The webcomic that uses the proleptic Gregorian calendar.
The many-worlds interpretation of quantum mechanics says, more or less, that every time a quantum event occurs - such as the decay or non-decay of a radioactive nucleus - the universe bifurcates into two new universes. These universes are the same, except that in one of them the event occurred, and in the other it didn't. Since quantum events happen all the time, our universe would be splitting into an incredibly large - perhaps infinite - number of new parallel universes all the time.
Given this, you can extend this hypothesis to any event which has a probability of occurring in multiple different ways. In particular, every time you face a binary decision, the universe bifurcates into two new universes: in one of them you chose one action, and in the other you chose the other action.
Unfortunately, these momentous events of universe creation pass most of us by unnoticed. We all have superficially more important things on our mind most of the time. Which is a great shame.
So here is a decision for you to make which has no implications other than which universe you choose to create. Choose wisely.