1. When you have a fried egg where the yolk is still runny.. you then eat all the white separatly and leave the yolk intact, ready to put in your mouth at once. Yolksplosion occurs when you bite down into the runny yolk and it pours out in your mouth.

2. When you have a boiled egg with a runny yolk and you dip your first soldier into the yolk, breaking the membrane and releasing the liquid.

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.