I love going for FTFs, and I love paying it forward when I get one. This location and hide is nothing special, but how the container came to be is a special little story to me.
When I was in high school I was convinced that I had found the love of my life, but we only had one class together and she sat all the way across the room. Passing notes was just too risky. So I hid the notes in a container of this exact construction and passed them to her anyway. I thought I was incredibly clever. She responded well to the gesture, I swapped seats to sit next to her, and we became BF/GF. I would later learn that the teacher was on to the whole scheme of mine, but allowed it because we weren't being disruptive and we were both getting an A in the class.
Things didn't end up working out, but it was fun while it lasted, and I'm still proud of my means of secret note smuggling.