Although a few have facetiously mentioned religious history shifts and one on the plague.

Well, you could look at tools and wonder what would have happened to homo habilis without tools or homo erectus without fire, I suppose. Or consider what if horses, donkeys, and camels had been butchered for food or had been wiped out due to climate change, as what occurred in the Americas 10,000 years ago? If they and cows and oxen, the so-called beasts of burden, did not exist in the Eastern Hemisphere, what would have happened then? Or conversely, what if such animals had remained extant in the Americas? Would I have then inherited a mutated gene that would allow me to process bovine milk after the age of 4-5?

The game of "what if" I suppose is fun, but it's more fun when such queries are then turned around and applied to what did transpire.