I was not totally listening. I was not completely seeing, I was not be aware. And, I sadly missed many grand things. And so it is in the world of academia. Every student is valuable.
Every student starts with a clean slate.
It's OK to be disappointed or even frustrated, but don't stop loving them as persons. Some have asked how I do that. With difficulty, I assure you. And, not always successfully. My usual answer is that I meditate before each class and focus myself.