I met with a student about an assignment recently. Stu wanted to run an idea about organizing a paper with me; zie'd started off thinking X, but was now thinking Y (a MUCH more sophisticated understanding), and wanted to know if it was okay to reflect that in the paper, and if it was, how could zie do that.
I told Stu that I was impressed by the development, and we went over one or two organizational possibilities. Stu was in that moment of having realized how much zie is learning in classes (not only mine) and wanted to talk about hir learning, and it was delightful.
Often, students learn a lot, but it takes time to realize that they've learned, and they're long gone from our classes by the time they realize it (if ever). But every once in a while, you get a student who's ready at just that moment to learn and realize hir learning, and it's so fun to hear about hir excitement.