In thinking this, the word "profundity" came into my mind for no apparent reason. I certainly don't think of myself as profound, rather just an ordinary person. But then I realized that people aren't ordinary, each is capable of being interesting and of teaching you something about the world and about yourself. And that is when I thought of the word "profound". Each person in the world can simply be described as "profound".
According to the Oxford English Dictionary, the word, profundity, is a noun meaning, "1. a. The quality of being deep; great or vast depth. b. A very deep place, an abyss; the deepest part or parts of something. Also fig. Now rare.
Wow, so much for a word I thought about on the way to work. Friendship is profound and I do think that people have those "great depths" should they choose to delve into them and explore them fully. Sometimes you choose to embrace the depths of a relationship and sometimes you don't.