imagine if...

[Troublesome Lagomorph]

there already are, you fail.

what if right- and left-hand dominance where reversed?

I'd be a lefty.
What if gravity would occasionally reverse itself.

 

[BuckminsterF]

what if everyone had superpowers?

Then everyone would be super so no one would be and there'd be mass existential crisis
what if advertising (anything) was illegal?