It's only arrogance if you're wrong.
Someone recently called me arrogant. I'm not sure that I really am, but when I was talking to a friend recently he referred to himself as having "earned arrogance". He grew up in the foothills of Lake Elsinore, the son of a White Trash family. His brother was in a Vietnamese gang, his mom and dad on and off again alcoholics and drug users. When I would drop him off at his house, there would be police helicopters hovering over his neighborhood looking for convicts. By all means of circumstance, he should have ended up knocking up some ghetto chick and working at the casino. Instead he put himself through school and is now a teacher who is planning on getting a Master's degree soon and go into administration some day. Teaching isn't my thing really, but good for him for doing his thing. He's doing what he always wanted to do. He's educated and has a steady career. So is it okay for him to be proud of his accomplishments and achievements? Yeah.
I think people have this misguided thinking that its bad to feel proud of your achievements. Its not like he's overbearing and throwing it in people's faces like an obnoxious asshole, but really he's come a long way. So, I'm not sure why people think we should all act like its no big deal, because that is denying all the effort it took to get to this place. And that's not fair.
I didn't go to Harvard, and I am the daughter of a lower-middle class family whose parents are smart but didn't really finish school. (Dad did recently though) My parents believe in perserverance and hard work, so paying for my schooling was never an option for me, even if they did have the money. I had to find my own way, and I did. And yes, I consider my life a success. And yes, I feel I have much further to go. And I will. That's the thing about success, its always over there. So, is it wrong of me to say that I'm successful? No. Absolutely not. I make no apologies for myself.