Ten years ago...well, there's always the bullies that antagonized me in childhood.
And there have been a few select individuals here that I put in the same category (though that was not ten years ago).
But does it matter though?
Like others have said, I don't know if it's "hate". I try not to hate because I feel like hate is something you have to do actively, which means it costs you energy to keep up the hate. It drains you. I try to keep it down to "strongly dislike", because it's true, I don't think they are good people, I think they knowingly and intentionally act in a harmful way because they get their jollies from it.
I used to say, if I ever saw them again, these childhood bullies, I would fight them on the spot, like I should have stood up for myself before. I used to think insulting and swearing at them showed them I was pushing back, but since then I've re-thought about it - I've learned that bullies like attention, even negative attention. And they also like feeling like they got to your emotions. So when you say or do something that makes a bully feel like they got to your emotions - that you care about what they think of you - it gives them satisfaction, it makes them feel like they have power over you. They get validation from it, which then encourages the bully to keep doing it, to come back for more (doing nothing isn't the answer either, though - that just looks weak, and also encourages bullies to continue - I feel like you have to stick up for yourself, you have to say something strong enough, but at the same time, not so angry that it makes the bully think that they actually made you mad). This has been a huge realization for me, that changed the way I think about these people and situations.
It made me think that it would be better to act sarcastic or dismissive towards a bully, rather than angry and confrontational, because that's what they want - they want to know that they got to your emotions, because they are immature, they're childish. I guess they don't have enough to occupy them, to get their kicks a different way. I guess they did it because they thought I was weak, but that's the personality they choose to have - I'm not responsible for it. It dawned on me one day, what do they think they're denying me, that makes them "higher" than me? Their approval? Inclusion in their little group? But if that's the kind of personality they have, I don't want it anyway. So the only thing they can deny me, is nothing I want or care about. They did harass me and treated me hatefully - they did try to destroy me, and thought it was a perfectly acceptable, desirable thing to do. At the time, a physical response might have been necessary. I think they're trash people for the way they treated me, like, what kind of person thinks it's OK to treat someone else like that? But at the same time, being the way they are just self-identifies them as people I want nothing to do with, whose opinions I can disregard. Their personalities suck, but it's not my problem.
So if I saw them today, I don't think I'd get all mad and physically fight them after all - that's just giving them what they want. Instead I'd just brush them off, in a way that says, "I don't think you're a good person, and I don't care what you think." They're irrelevant to my life now. And I really don't care what they think of me. So all in all, dislike? Yes, strongly. But actively hate? I guess not. I'd rather just act like they don't exist. I can't, and don't forgive, but I can forget. I think for me, that's healthier.
So, it's easier to just default to bitter apathy than it is for me to continue holding onto past things that I can't do anything about. 
It's a better expenditure of my energy that way. 
