If something is so nice that you have the urge to destroy everything around you.

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.

When describing your (best)friend to people who are trying to say she's mean or violent and know she's a great person but you somewhat agree that she has violent tendencies.