Who said "The real tragedy is that we're all alone in our own heads."?

This quote is attributed to BoJack Horseman.

The real tragedy is that we're all alone in our own heads. - BoJack Horseman

"The real tragedy is that we're all alone in our own heads."

BoJack Horseman Solitude

"I'm a real piece of shit, aren't I?"

"It gets easier. Every day it gets a little easier. But you gotta do it every day. That's the hard part."

"When you get sad, you run away. But sadness is just another monster chasing you, and you have to stop running eventually."

"You can't keep doing the same thing and expecting different results."

"Sometimes being the best means being the loneliest."

"Solitude gives us time to reflect on what matters"

"I'm not good with people, never have been."

"I feel like I'm disappearing."