I find a singular pleasure in occasionally hiding clues in lectures, when I have time to think about it in advance. Using 5773 in a numerical example at Rosh Hashanna, quoting some book without attribution, having a pictorial reference to my favorite children's picture book, etc. Then, if a student catches on, it is as if we were sharing a secret in plain daylight. We know the hidden meaning the others are unaware of. We may exchange a glance, and then we know: I know that he or she understood me, and they know that it wasn't chance, and that I know that they know. We understand one another.
What is the point?
There is no point as far as I can tell. It's just nonsense. Most of the time it has no pedagogical value. But it is delightful.