1. Your favorite light that you own and why it is your favorite (and a picture of it if possible)
My favorite is Olight S15.
It’s tiny, has a tailcap magnet, nice mode spacing, great UI, runs on 14500, 1xAA, 2xAA, 3xAA 
It became even better when I installed a TIR in it. Next step will be swapping the LED for something more neutral white.