The differences between being alone and being lonely- more about memory too

Some people are really good at being self-contained and alone. Some people are really bad at being on their own, and turn it into being lonely. Sometimes they are the same thing, sometimes they are not. I've found you can be lonely with other people there - it's a state of mind.
I know other people who are always lonely on their own, some people who really want to be on their own and aren't lonely and some people who are never alone but are still lonely.

Sometimes you aren't alone even when there's no-one else actually there. Sometimes you take people with you everywhere you go even if they aren't there. Sometimes that's good, sometimes it isn't. If you know they will be somewhere you are going, or will be in the future, it's usually good, or at least ok, especially if you know that they are thinking about you the same way.
If you are wanting someone to be there and they aren't, that's usually bad, but it depends on the level of hope you have that they will be somewhere else you're going to be. If you can't lose the feeling that they'll always be somewhere, but they never are then that's really bad. If you are afraid that they never will be there and you still feel the same then that's probably the worst it can get. A bit like seeing the ghosts of people who aren't dead yet. That's how places get haunted.
There are places, sounds, voices, scents that trigger memories. Sometimes these make you feel sad because you've lost the person who made the memories happy, sometimes you're happy because you haven't - sometimes you really don't care. Sometimes you do, but they don't, which isn't good either.