There's nothing like a nasty cold to make you appreciate good health. The same goes for the state of the universe: Tweaking just one of the fundamental physical laws or constants, normally perfectly "fine-tuned" at the right values to allow stars, planets, atoms and life as we know it to flourish, could turn things very different — quite unpleasantly so. Imagining such a "bizarro" universe may heighten your appreciation for the norm.
Consider, for example, how horrifically unrecognizable the universe would be if it had formed with just three fundamental forces instead of four — if electromagnetism, the strong interaction and the weak interaction were all exactly as we know them, but that fourth force, the one that pulled together a bunch of rocks to form Earth and still keeps your feet firmly planted on the planet, never existed. What if there was no force of gravity?
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