Depends somewhat on the scar. (A major scar on the face can be hard to grow accustomed to.) Otherwise, I agree with Richard... they're a sign of living life.
They can even be badass! You can make up some great stories about a shark attack, having to massage your own heart, or having the record for the world's worst paper cut. When life gives you lemons... you know.
I'm incredibly apathetic towards scars. I have several that are incredibly noticeable except even I forget they're there. I don't normally notice scars on other people and one guy who I can recall having a large scar on his cheek I didn't even notice it when I first met him and even after I noticed it, it didn't stand out to me. I still thought he was unnaturally sexy.
I suppose some people will be uncaring, some will find them attractive, and anyone who would deny a date because of a scar is a shallow douchebag who isn't worth your time.
I find some scars sexy. I see it as a real human flaw, which is very sexy. I dont like people who pretend to be perfect or act like their shit dont stink.
As for your first outing in stitches and staples, I would have played that up REAL fast!!!
If that was me in the store, and saw people staring, I would have made my eyes wide open and stared directly into their souls and said "I SMELL FRESH BRAINS"!!!
I would have all sorts of fun with a scar as you described.
Them: "Oh my, how did you get that"?
Me: "I saved a little boy from a car wreck"
Them: "How did you get that scar"
Me: "By fighting off stupid people who ask me about my scar"
Them: "Wow, that must have hurt"
Me: "Why yes it did, let me know you how much" (getting out my pocket knife)
If you go in a gay bar, you can definately play it up there too:
Them: "OH gurl, where did you get that"
Me: "Oh this? It was from a bad trick"
Them: "What happened to you"
Me: "I was with a hot guy and told him I wanted to be ripped up.....so he did"
Them: "OMG, whats that"
Me: "Thats my fetish, wanna make me a new one"
As you can see, my sense of humor is on the dark side.
And no, Darth Vader didnt take me there, I took HIM there.