What is something the world would be better without?

It's kind of a side effect for us having regenerating cells. From what I understand it's an umbrella term for a variety of diseases that emerge from us living long lives with - relatively - versatile/adaptable bodies. In some ways it's amazing that our bodies work at all.

That said, it's not easy to be philosophical about it when you or someone you know is affected. Lost a family friend to cancer just a few months ago.