You would be shocked how little difference there actually is between most alternate universes.
Oh, granted, there's always going to be the odd one out. Well… actually, there are an infinite number of odd ones out. You see, the nature of the multiverse is that it's not actually 'multi' so much as 'omni'. Everything that could have possibly happened has happened, and more than that, it has happened an infinite number of times across an infinite number of universes. Therefore it is impossible for any universe to truly be odd, because any given universe is nothing more or less than the sum total of an infinite number of things happening or not happening in combination, and there will be another universe where the exact opposite things happened, and between them will be universes with all of those (again, infinite) things happening in wildly different or nearly identical combinations. And each of those will have an opposite too. And then there are the ones where nothing happened, ever, and the worlds where things have stopped happening. And there are an infinite number of those as well, many of them with subtly different definitions of 'nothing' happening, and sometime the nothing from one leaks into another and becomes something there because that universe has different rules of nothing, so what doesn't exist in one universe not only exists in another, it always has existed and always will exist, while in yet another universe it will never haven't not existed.
And just think: if you were one of my apprentices, I'd be quizzing you on this later. And people wonder why they traditionally don't last long.
In any event, my point was, there are many, many alternate worlds. And many of them are strange indeed. I've seen worlds where life on Earth took vastly different paths; a landscape made up of monumental crystalline mountains constantly wreathed in emerald lightning, populated by formless energy creatures that fed on magnetic charges. I've seen worlds where humanity evolved more quickly; a race of psychics and superhumans who make our greatest achievements look as transient and meaningless as children's sandcastles... and who tear their world apart in wars the scale of which we cannot even imagine. Worlds where man never evolved at all, leaving Gaia wild, cruel, and untamed… but far more beautiful and vibrant, in her own harsh way.
I once saw a world of nothing but shrimp. I tired of that one quickly.
But a surprising number of worlds are nothing like that at all. They're just… exactly what you know. One little difference, maybe two. One person's life is changed, and that's a whole different world. Even though only a select few people are affected, it's still a world all its own.
And sometimes, that rarest of rarities… sometimes, that one little change is just the first few rocks that signal an avalanche, and by the end, the world that used to be so much like your own isn't even recognizable. They say that a butterfly flapping its wings can cause a hurricane on the other side of the world, if it hits the air currents just right. They're not wrong. Sometimes, it doesn't even take that much.
And sometimes not.
And sometimes both. Or neither. Or all of the above, repeating infinitely in a cascade of possible and impossible actions and reactions across all of time and space.
Isn't magic fun?
-An Excerpt From the Memoirs of Kischur Zelretch Schweinorg. If you found parts of it confusing, that's probably for the best.
All things end.