If you don't explain clearly what your startup does, it will confuse investors. And confused investors don't find your startup intriguingly mysterious. They find it boring and lame.

Worse still, when investors are confused by your pitch, they won't even tell you. They're not going to work to interrogate your idea out of you. They'll just smile and nod for a little while, and then move on.

Here's a test of a good explanation. How close am I, after hearing it, to knowing how to reproduce your product? "Disrupt the $732 billion trucking industry." Terrible. "Self-driving trucks for long-haul routes." Great.