Missing the chance to say goodbye to someone leaving, usually witnessed by others who will tease and taunt you for it.
I watched my bf sitting on the bus and was waving goodbye. As I turned around I realized he missed my full moon failwave. The old man sitting next to him had a big smile as I looked back.
After I got home from the concert, I checked my mobile to see all of my friends had failwaved to me before I left.