When I was in grad school, my advisor was a prof who had done a lot of work on classroom management and motivation. One concept that she (and all the methods instructors) pushed was that teachers shouldn't allow preconceptions about students to cloud their judgment. For the most part, that makes sense. No one wants to start the school year with a teacher who has already made up his mind to hate you. It's also important for teachers to make sure that they're not unconsciously pigeonholing students based on anything from their home address to their interests to the fact that the kid's older brother came through five years ago and was a raging @sshole. So the message they preached was, Give the benefit of the doubt. Treat each kid as an individual. Make each day a fresh start. Disapprove of the behavior, not the kid. No naming, no shaming, no blaming.
However.
(You knew that was coming, didn't you?)
There is a big down side to this approach, which is that I think kids aren't aware of the impact that their actions can have on their reputation, or they think that it doesn't matter. It's even ingrained in the language we use - "Maddysohn doesn't make good decisions," instead of "Maddysohn lies like a rug;" "Jaxon has poor impulse control," instead of "Jaxon cheated on his test." Kids have absorbed the message that "there are no bad kids, just bad choices." Now, I agree that everyone should get a chance to have a fresh start and be judged on his or her own merits. I also have had good luck over the years with ignoring reputations and giving the occasional mulligan, especially if I'd never had a bad personal experience with a kid. But kids need to understand that the do-overs only go so far, and that people out there in the big, bad world DO judge you by your actions, far, far more than by who you think you are. If you're 13 and you lie to your teacher once, maybe even twice, well, everyone does stupid stuff when they're young; that's why you're not allowed to buy real estate until you're 18. But when you're 13 and you lie to me three, four, five, six times or more, even after I've caught you in your lies multiple times, then you are a liar. If you take other people's things, even after you've been found out, then you are a thief. You become what you do, and if you cheat, bully, backstab, lie, steal, etc., on a regular basis, then you are no longer a nice kid who happened to do x, y, or z - you ARE x, y, or z. It doesn't matter if Mom managed to bail you out again, or you're going to therapy, or if it's unfair that you've always had to follow in your older sibling the honor student's shadow, if you choose to engage in these behaviors over and over again, then people are going to assume that you will do so in the future, and will treat you accordingly.
I'll close with words from my favorite epigrammarian, Ben Franklin. (Good ole Ben; he had something to say about just about everything.) "Glass, china, and reputation are easily cracked, and never mended well." Oh what the hell, why not chuck in some of the Bard as well? "Reputation, reputation, reputation! O, I ha' lost my reputation, I ha' lost the immortal part of myself, and what remains is bestial!" And, for the grand finale, some words for the ages from one D. Stephen SomePig, my very own dad, who used to say, "Do that again and I'll knock you into the middle of next week." Ignore all these at your peril.