Why isn't it a doughnut?

The universe is expanding. One day, it will expand to a lifeless, formless thing.

But, to me, logically, this is a really silly scientific idea. Every time I hear it, or read it, I think doughnuts!

A doughnut is a fascinating shape - delicious or mysterious take your pick!

So I want to ask all miserable, depressing, deluded scientists out there - why isn't the Universe a doughnut?

And if it were - how could you ever know? It would be expanding and contracting simultaneously and your math would need adjusting. But a doughnut shape is what you are missing. Believe me - I know. Doughnuts are the answer! They are the theory of everything.