I think lil's definition is the one that's more conventionally accepted- your personal "baggage" described above seems more like possibly the result of baggage rather than the baggage itself. But looking at it both ways:

1 (your way): problem as I see it is that the person least qualified to identify my most detrimental qualities vis a vis interpersonal relationships is me. Reason being, I have a skewed view of myself given that I have access to my inner monologue. So how I see myself doesn't necessarily align with how others see me, for better or worse. I might think I'm worse than I am, because I'm privy to all the negative thoughts that others have no access to. Likewise, others might recognize my less savory aspects long before I do. I have my own value system, and I rate my thoughts/interactions by that subjective value system; are the things I see as "bad" in myself actually the qualities most detrimental to my outside relationships?

Example: from my perspective, my most worrisome qualities: temper, anxiety/depression, lack of follow-through. However, when I posed the question to my wife, she saw little of those qualities leaking out into the real world in a meaningful way. She said that my "baggage" (by your definition) had more to do with doubts re. self worth when it comes to my professional/creative legacy. I've been struggling for a long time with how to define myself as a productive member of society, and that ends up coloring my interactions and world views. This is so fundamental that it would have gone right over my head if it hadn't been pointed out to me.

Another example: my two best friends from high school came up with a nickname for me a couple years ago: Scam. Because, they say, I'm always looking for the angle and fixing to turn things to my advantage. The name, and the circumstances under which they chose it for me, seems absurd. We were out on a drunken bender, I had to pee, and without telling anybody what I was doing or why, I walked right off the path, crawled over the patio of some downtown law office, hopped a hedge and let loose behind some trashcans. How is this evidence that I'm always looking for the advantage? I dunno. I see it as evidence that my bladder is small and I've been forced to make a habit of constantly mapping out every secret place I might be able to unleash in public. But they insist it's just a good allegory for how I am with life. Always scammin', man. Wouldn't have considered that without their input. But then, maybe the best scammer is the one that convinces himself he's not a scammer?

2 (lil's definition): I'm an occasional subscriber to the theory that we ALL carry baggage from childhood; be that your run-of-the-mill high school baggage or, if you're unlucky, deeper stuff from before, either from within the home or without. I had some household drama that I still carry with me, but I'm not going to pretend that I came from a broken home or anything. My home life was just fucked up enough to teach me some valuable lessons about stress and how you manage it around your kids; not fucked up enough to imprint on me and negatively influence the way I treat loved ones. As for high school, I'm pretty sure that no matter how popular you are, no matter how well-adjusted, you WILL come out of that shit show with some baggage. If for no other reason than we're a mess in high school on like a fundamental, physiological level and any halfway traumatic experience will gum up the works. Romantic stuff, particularly. Reading these comments reinforces this idea for me.

Personally, I went through a series of weird relationships in high school. Some weird in all the old boring ways, one weird on a whole other level that sent ripples down the emotional line for years and years. Baggage for days. I've since then shed almost all of that baggage and good riddance, but it took some hard work, self-reflection and an ultimatum or two.

Makes me think that maybe high schoolers should be banned from having relationships. Oh, they should have lots of sex, but they shouldn't get anywhere near relationship status, because who knows what love or caring is at that point. You're liable to do more long-term damage than good. (EDIT this might have been a shitty generalization. Input welcome.) Then again, maybe this is just the onset of crotchety adulthood talking? I'd be interested to hear about this from the perspective of the high school kids around here.