There are just so many possibilities for human existence. If there is any purpose in it — other than something that happened by random chance — it seems a bit limiting for each of us to have just one shot at it. For one thing, it would be nice to experience both the genders.
But suppose your passion is a sport — say soccer. Just think of all the possibilities that abound within the confines of that game — the different positions to be played — the levels of play — from just dribbling a ball in the childhood playground to captaining your national team in the World Cup — the national teams you could captain, from Afghanistan to Zimbabwe — and all the professional (and non-professional teams) you could play for, coach, or even own — and all the injuries who could have — and all the fame you could enjoy — to say nothing of all the fun you might have.
It could take a hundred thousand lives lived on every soccer-playing planet in the universe to experience every possibility for a life that revolves around the game of soccer. And by then, you’d be pretty darned good!
And when you were finally done, God would congratulate you — and suggest you do it all over again — this time as a woman — then with a physical challenge — perhaps even as a blind person.
One million lives later, you’re still not done with playing soccer (although hopefully getting tired of it by then) – let alone any other sport — let alone the arts and sciences — let alone politics and religion — let alone being an ordinary person raising a family.
Regardless of what you want, how could the one life be enough?