Alone

“Why do people have to be this lonely? What's the point of it all? Millions of people in this world, all of them yearning, looking to others to satisfy them, yet isolating themselves. Why? Was the earth put here just to nourish human loneliness?”
"In this world, there are things you can only do alone, and things you can only do with somebody else. It's important to combine the two in just the right amount."

These two quotes by Haruki Murakami define the two categories of "alone" for me. All humans, I would think, feel loneliness in sense of the first quote. The lack of being whole or complete is the base feeling of loneliness. It is the sensation of feeling that something is supposed to be there but is not. The next stage is the lost and nostalgic feel. It was a book or poem I read in world literature that describes this feeling pretty. It is the feeling of how roots expand to accomodate for the soil but having the soil be washed away only leaving emptiness. I call it the "once was." Another feeling of loneliness is the outcast or the "no one knows how you feel" thing. That is the feeling of falling down a well but no one going down with you. Yes, people on the surface may care deeply about you and want to get you out, but they have no idea what it is like. It is a separation; a distance.
The other meaning is simple. It is the need to be in solitude. Time where you need to be separate from the interaction to breathe, face inner demons, binge on netflix, etc. No one wants to be smothered.