Not sure how I came across this thread 11 years after the last message, but while I'm here...
As for myself, I did tease someone pretty badly in 4th grade (other than that, there were a few one-off events), but I felt bad about it and stopped... It wasn't "me", and I wasn't particularly "good at" being a bully.
I was bullied in elementary school, and it became particularly harsh in middle school. High school, less-so (although it didn't stop completely), but I'd become more reserved and went out of my way to avoid situations where I felt uncomfortable. It was definitely more verbal than physical... I was never beaten up, and the only times (once or twice) it got physical were when someone I was (at the time) best friends with joined in on the name-calling for a period of several months (in an attempt to fit in), and there was the added feeling of backstabbing. There were plenty of threats of being beaten up, and at times contact was made, mostly by 2 guys who were actually brothers. One time comes to mind where I was pushed onto a table by one of them, and I reacted by kicking him in the chest with both legs, knocking him on the floor... And that was the end of it. The two of them weren't particularly big, and it was always one of them at a time, not both of them, so I wasn't scared of being beaten up, it was more the relentlessness and cruelty that someone would actually want to that got to me... The way I saw it, if there was a flight, we'd both get hurt no matter who won, and I didn't want that for either one. They weren't the brightest, and I only saw them in passing a few times after my freshman year in high school (one dropped out, the other went to juvi but showed up at graduation anyway), so I never gave them much thought after that... It was obvious that they weren't going anywhere, and I was cool with that.
The many others that were all verbal, though (no matter how constant or brutal), I hold no grudges, I let it all go after high school... Did it have lasting effects? Sure... I found out early in college that I have social anxiety. But I figured, what kind of person would I be if I harbored resentment towards anyone because of things they said as children... I would basically be hating a child. We all say dumb s--- as kids, and there are plenty of things I regret, so I'm sure they all do as well. And I've crossed paths with many of them since then... and everything was cool. We were all friendly, like nothing happened. It was good to see that we've all become better people. One that I never had the chance to speak to again, though, died tragically a few years ago, in his mid-late 30s. Even though we never got along, I was saddened by the news.
Ultimately, I think the "anti-bullying" campaigns are a little ridiculous, and about as effective as DARE was in curbing drug use. The most petty bullying is shown alongside the most extreme 0.0001% of outcomes. Like most all top-down collective solutions, they amount to, "We need to do something, this is something, let's do it," with no realistic goals or expectations for how they'll play out. Rather than punting to a higher authority, the overwhelming majority of bullying is the responsibility of the parents, to raise their children to have sympathy for others.