Why don't more people carry a knife?
Before I go on I will make this clear: This is not the place for a silly weapon or self defence argument.
My knives are precious tools that I'm attached to, much like pets or cars. Sitting here on the couch in my robe pocket is a little 2" blade. I've fixed fuse boxes and took off license plates with my multi-tool, cut fruit with my knife, chopped kindling with a heavier one, made roasting sticks, cut thread, fishing line and pizza.
I use my knives every day. And every time someone asks to borrow one I always ask why they don't have one. It is usually a shrug and a moan instead of an actual answer.
So I implore you to invest $40 or whatever into a nice Cold Steel, SOG, Gerber, Case, Schrade or Winchester or whatever catches your eye. See how much it helps out opening those pesky bags of jerky, cardboard boxes or thick plastic packages. Try a Werner or Victorinox or Leatherman!