BMF stands for beardmanface who is a british streamer who commonly plays dead by daylight a hunter killer type game and is also known for his laugh,humor and haircut go follow him at twitch.tv/BeardManFace or his brother twitch.tv/PunchMouthTV

sincere condolences Demandedsoul

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.