I'd think that it'd be incredibly rare for anything to happen with "A" cause, as in singular. Pretty much everything has a multitude of causes, to the point that it can become difficult to actually figure out whot actually caused it in the first place.
A deluge of over-information can seem like no information at all.
The biggest issue will boil down to the creation of everything; was there a cause to the big bang or not? If nothing existed before it, then there could be no cause, and nothing to affect as nothing would've existed TO be affected. Which makes no sense.
Which leaves us either with A: the universe always existed in some way shape or form, B: divine creation, or C: something existed outside our universe (another universe? branes are used in M-theory for example) caused the creation thereof, but was not actively existing within our universe, but would mean that the outside existance was in fact infinite, even though our universe was only finite.
That's about it really, everything else is affected by everything else as gravity has literally no end point, it is infinite in range, even if it's reduced to such an insignificant amount it may as well not exist, when yeu have trillions upon quadrillions upon quintillions of pieces of matter and energy in the universe all interacting with each other, it adds up, even if each individually infinitely small nudge is unable to be felt alone. So yes, everything is directly connected to and affecting every single other thing in the universe. As there's no apparent lag time or travel time for gravity either, yeu are simultaneously affecting every single thing in the universe with yeur mere existence at this very moment. Neat, huh?