Humans love to be surprised (as long as the surprise isn't a nasty shock). As thinking creatures, our ability to develop an accurate working model of the world depends on our ability to spot the unexpected. Surprise is a great mechanism for rewarding that ability.
Wharton conducted a study of viral videos. They had research subjects watch videos that either generated about 1 million views, or 100 million views. The key difference between the two groups was that the 100 million view videos involved something surprising.
I see the same thing in startup pitches. The most effective pitches involve saying something like, "You probably don't know this, but...." The surprise is key. Every investor hopes that a company has discovered a rich market that seems obvious in hindsight, but which others have overlooked. Being surprised by a pitch is one of the key indicators of such an opportunity.
So as you prepare your pitch, ask yourself what's surprising about you and your business. It should probably be one of your key selling points.