My game crashes when I try to load a single player world!

My game crashes when I try to load a single player world!

I expected the single-player world to just open when I selected it, but what actually happened, was that it tried to load, and then crashed.

1. I opened the Minecraft launcher.
2. I selected my 1.10.2 profile
3. I pressed play
4. I selected the single player world I wanted to play
5. And then it crashed