OK, before we get going, im a 17 year old male, live in Canada, and i consider my self mature. Now on with the story.....
I as doing a Bio lab and the razor blade i had to cut open the pig with was dull as all get out, so i take out my leatherman and used the clippoint blade, needless to say the piggy opened right up, but my teacher walks over and gives me dirty looks, so i slip the leatherman back into my pocket and pretend nothing happened. After class she calls me over, and says "young man why do you have a knife in school" i replied "well the ones you gave us just wernt good enough so i brought my own" needless to say she scowled and i went on to explain that i carry it only as a tool and using it as a weapon was the furtheset thing from my mind. In the end she let me go, and i didnt get in trouble, tho it was close. I still carry it to school but no one notices me using it anymore.
So my point is, just because im 17, people look at me funny when i prouduce a prefectly usable tool from my pocket, I find this rather hurtful, to be watched, just because I have a knife
Never underestimate the power of human stupidity.... You'll see more of it as you get older. But I'll give credit where it's due, your teacher realized she was acting like an idiot and decided not to continue.