I once started developing a chatbot, super easy and simple, a MySQL backend for the QA stuff.
I then started to think on the most modular way to "reuse" the same QA system, and got stuck on it for around 3 days (while doing other things).

Obviously the chatbot stuff could'nt leave my thoughts , and I remember it was a saturday morning, I woke up super excited and just started writing down what my sleepy me was engineering while I was dreaming.

I still have the same system implemented and I'm expecting that some day, in the future, I'll have to rewrite it, and I hope "sleepy-me" helps me again, this time with an actual interesting solution haha