Usually a chill guy who will only get mad at you if you get on his nerves he’s never rude to people unless they are rude to him so don’t piss him off and your chill with him

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.