"I cannot tell you how much I have enjoyed being in your class, how much I learned, or how much I gained personally just from knowing you. Thank you so much! I hope to build upon our friendship. Take care, and thank you for everything."
"Just wanted to say I'm so glad you came to AI, and thanks for being a pretty cool teacher. I really appreciate all the work you have put into the class. Thanks for being willing to take us all on and teach us what you know. I look forward to the rest of the term"