First, because of my rule (not one step without a knife), because it is the most useful tool any if you get in a survival situation or something, knife is your best friend,
Second, because it opens lots of stuff really fast, bags of chips, etc. and you can usi it for much more...And yeah, I have this really uncomfortable feeling when Im without a knife for longer than few minutes. Like something is missing, something is not right.
I have been carrying a knife since I was 3. (did I get the tense and ing-form right?)
Because the gun on my hip doesn't cut well, like the knives in my pockets.
I carry one because I love knives.