Your other half, your one and only, but most importantly the person you would most likely die for. They are usually your counterpart, but can be your best friend and your rock when you get home. Always appreciate your banhegh.

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.