Useless information.
So I went to a Moomins Q&A/Documentary viewing recently, the Q&A was hosted by Philip Ardagh. Towards the end of the Q&A  Mr. Ardagh said something along the lines of “Something that bothers me about Moomins merchandise is-- well, can anybody tell me the main difference between Moomins and Snorks?” I knew it, I knew the answer, it was my time to shine! My arm shot up, I didn't see any other arms, naturally I was picked.
“SNORKS CAN CHANGE COLOUR!”
I was right. I was so pleased that my retention for mostly useless detail had a purpose. Afterwards in the Bar Philip Ardagh recognised me and said “Now, here’s a man who knows the difference between Snorks and Moomins!” He might as well as said “Here’s the man who saved the king!” I felt like a hero, and it sounds stupid, but something I actively do, a thing that others often berate me for, is retain details like this.
Life is too unpredictable to say whether information is useful or useless, so if you’re the type to absorbs facts; KEEP ON ABSORBING.
