Cau-tion-istic/ˈkôSH(ə)n'istik
Adj.

1. a person whom is "cautiously unoptimistic" or both mildly optimistic and greatly pessimistic.

2. cautious to a fault.

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.