"This one on me knee is from when I went hiking."
"This mark is from when I played the best football game ever!"
"Oh, that's a shark bite from scuba diving in Australia."
"Here's where I lost my leg in 'Nam."
I don't have any scars from wars or extreme sports, but I definitely have a few of my own anyway. For example, I have a scar on my leg from when I tried to sew when I was about 7. I also have quite a few on my hands and arms from being burned while baking. To me, they are reminders of the things I've done in my life.
Other scars can be good reminders, when you look at them and they say to you, "Be careful, stupid!" Take, for example, the scar I am now going to have on my middle finger from not remembering my knife safety rules. I won't go into detail, but lets just say it had something to do with a serrated knife and a loaf of ciabatta.
My pastry degree did not require more than a brief overview of how to properly use knives, but the students who did the culinary school program had to have a full course on knife skills.
So, unless you want lots of scars to remind you of all the meals that you have cooked, I suggest that you read this article (and watch the video) about basic knife skills.
Also, just for fun (and since I have no pictures today), I am going to search you tube for "how not to use a knife" and post for you the first video that comes up. Let's see what happens, shall we?
I kid you not, that was the video. You can it search for yourself if you want!