A quick thank You note to a teacher that you don't like
I had a learning experience with you this year. I learned stuff that I never knew before. You helped me improve as a writer and I appreciate this. I just wanted to say Thank You.
Usually if you don't like someone, you won't write them a thank you note. But, perhaps you're taking the high road here, and thanking this person because they taught you something despite having personality differences.
Or maybe your parents are just making you...
Either way, if you're going to write someone a thank you note, you should make it sound sincere and gracious despite your personal feelings for them. So, you'll want to drop phrases like "had a learning experience".
That just doesn't sound too grateful...
Try this instead:
I know we may have had some differences over the past year, but I'd like to thank you for the time and energy you put into teaching us. I've learned a lot, and I couldn't have done it without you. So, thank you.
Always remember that teachers talk to one another. Even if you'll never be in this teacher's class ever again, she'll probably talk with your next teacher about you at some time.
So, smoothing things over as best you can is advised.