A baldsack is a ballsack with no hair. However, you must have had hair on your balls before to have a baldsack. The people most likely to have baldsacks are people on chemo, old people, and anyone with no body hair, like Buddhists.

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.