Even given how much I write (or perhaps that's a proof of its own), I am a classic introvert. While I've got a number of people I'm friendly with, I don't actually count many people as "friends". I'm one of those people for whom "friends" are people I share a deep connection with. Everyone else lies somewhere outside of that term. Hard to explain if you don't share a similar measure for what you refer to as "friends".
At any rate, my father was one of the few people I counted as a friend. He and I could talk about anything and everything. From the most cerebral to the most inane of topics. We could speak briefly. We could speak at length. We could convey volumes in very few words and we could spew volumes of words and say next to nothing. More importantly, we could exchange ideas without taking personally things that most others would take personally.
Really, my dad was one of the few, possible only people in my life that I could speak freely and fully with. Sadly, with him gone, I've no longer got such outlets. And, while I very rarely availed myself of that outlet after I moved out, I always knew that it was there if I ever really needed it. Now, that's gone. Now, I have no one really left to speak freely to.