I've told this story before here. About 10 or 15 years ago I had a student in my Precalculus class. Brian was bright and and pleasant and did well, but didn't speak up much in class. After graduation he went on to the Merchant Marine Academy. While there, he was in an accident (slipped down a ladder or flight of stairs and died.) Along with his other teachers I attended his wake. The thank you card I got from his mom is something I'll treasure forever. It spoke of how he enjoyed my class, and loved having me as his teacher. Remember, he was an 18 year old boy--- they don't typically rave about their math teacher at the dinner table. I still have the note upstairs. I've gotten lots of gifts over the years from lots of students. But this one is one I'll always treasure.