I used to read Seventeen all the time, but I'm no longer a fan. It indulges in celebrity-worship, it engages in colossal overuse of italics and exclamation points, and it seems designed to make readers feel as bad as possible about their bodies.

In my eyes, the biggest offender is the magazine's Body Peace campaign. While its stated purpose is to make girls feel better about their bodies, it seems to steal confidence from the girls most likely to lack it. The Body Peace feature often prints letters like one from a girl who wasn't hurt when someone called her “thunder thighs” because her legs are not fat, but muscular. The only reason the insult didn't hurt the writer was because it was inaccurate, which seems to imply that if a girl is insulted accurately, it should indeed hurt her.

Every Body Peace feature is accompanied by photos of girls who are, by conventional standards, beautiful. I wish they would include a broader range, because if girls as gorgeous as those need reassurance about their looks, I guess there's no hope for me (or the majority of regular people).

However, there was a moment this year when I actually appreciated that column. One of my friends was upset about a chemistry test. Trying to soothe her, another friend and I told her that we knew she'd do well, and that even if she didn't, we wouldn't love her any less. Still anxious about the test, she said that if she failed she'd love herself a little less.

Regardless of whether my friend's declaration was overdramatic, it bothered me. Loving herself less because of a grade would be beyond absurd. Sure, I wanted her to do well, but her grade on one stupid test was so much less important than who she was as a person. If I reacted to her performance on a test in that way, it would be ludicrous, and would make me a terrible friend.

But on another level, I understood her feelings. When I messed up in some way – got a bad grade, broke a glass, gained weight – I would be furious at myself: Why am I such a moron? I'm a hopeless klutz! I can't believe how tight these jeans have gotten! I fail at life!

As I thought about this, I remembered an excerpt from that silly Body Peace column: it had instructed the reader not to think anything about herself that she wouldn't let someone say about her friend. Then, in all its fantastic obviousness, it hit me: you shouldn't hate yourself for something that you wouldn't mind in a friend. Your friendships, I'd wager, don't change when your friends get bad grades, break glasses, or gain weight, because things like that are unrelated to who they are and what you like about them.

I began to realize that, just like me, many of my friends did in fact get super upset with themselves over these sorts of things, and the more I thought about it, the more I realized we were all being ridiculous. You would be a terrible friend if you loved someone less because she didn't get into an Ivy League college or because he dropped his books. Using similar imperfections as a reason to obsess over why you yourself stink isn't any better; all it means is that you're being terrible to yourself.

More often than not, the things my friends beat themselves up over aren't just irrelevant to what I like most about them – they're not even related to what I like least about them. If I am honest with myself, I know this applies to me. For instance, I readily obsess over how much I snap at my brother, but what I really don't like is how easily irritated I am by him. But when I obsess over the snapping, I am both being mean to myself and completely failing to address the real issue.

I would guess that most teenagers engage in this kind of behavior. I think of it as figurative self-mutilation. Like physical cutting, this behavior leaves you with scars (in this case, psychological ones) while failing to address anything that might actually be wrong. Sometimes emotional self-mutilation takes place entirely inside your mind, cutting you off from others, but at other times it imitates the cry-for-help aspect of physical self-mutilation – maybe you can get your friends or parents to reassure you that no, the nearly invisible zit on your chin won't prevent you from getting a prom date. But it's reassurance that, if you were being honest with yourself, you would know you didn't need, because what you're actually worried about is your inability to dance.

Once I woke up to the phenomenon of emotional self-mutilation, I decided I had to quit. It was making me unhappy with no chance of helping me improve. Now, when I catch myself beginning a self-criticism, I ask myself whether it's something I would criticize a friend about. If it is, then I recognize it as valid. If it's not (and it's usually not), I decide to be a friend to myself and let it go, and then I figure out if there was a valid self-criticism behind it. Once I've got a valid criticism in hand, I can finally begin fixing what's wrong.

I'm still not a fan of Seventeen. Years of reading it left me with an annoyance at pop culture portrayals of teen girls, an encyclopedic knowledge of hair products I have never used, and the feeling that I've wasted a lot of time. But its most irksome column also left me with something positive: the ability to break the cycle of emotional self-mutilation. And that's one bit of knowledge I think almost everyone could use.