Too many "No's" in the world?

I love the fact that we have 26 letters and 10 numbers and do EVERYTHING with them! I walked round my local hardware store tonight snapping happily away with several bemused stares. Top tip- carry your would-be purchase boldly. It also helps to grin insanely at times.

When I looked at the missing letters it got me thinking about why they were the most common. Our negativity? Or something else? What do you guys suggest...