Life happens. I’m not the first author to write those words, and I won’t be the last. Our goal should be just to roll with the punches of life as well as we can.
In the back of my head, I keep remembering one of my mom’s best pieces of advice: “Never burn a bridge if you can help it.”
Even if you’re never going to be friends with someone, there’s no reason to be mean. Do your best to be civil when you have to interact, and if necessary, avoid the person as much as possible. However, you never know when you might run into him or her in the future, so it almost always pays to be nice.
If you have a teacher who doesn’t like you, hang in there. You’ll have another teacher soon enough, and that next one will probably like you just fine.