It is pretty rare for me to feel lonely. After sharing a home with siblings my entire childhood, room mates all through college and living with my partner for 10 years, I have learned to relish my time alone. He is great, but having to think for two when it comes to everything from watching a movie, to having lunch... a little me time keeps me sane.
I am in tune with Boiwonderkind's thoughts about loneliness...
I think the only time I find myself feeling alone is when I am around other people who maybe don't think like me or who need a lot of attention from me. It could be a dinner party, meeting a friends friend or their new partner, at a gay bar when Beyonce comes on and everyone loses their shit except for me or yes, even my own birthday party.
For example. You come to a revelation about love or life and you are all jazzed to share it , so you do.. but it doesn't go over as well as you had hoped. Sitting across from someone and wondering who is this person and how have we been friends this long makes me feel alone. Not the "Oh my God, I am going to spend my life in a one bedroom house talking to a cat" sort of way, but the existential, what does it all mean? sort of loneliness. On the flip side, when you share ideas and get all excited about the others thoughts and make each other think more deeply, you feel so utterly connected and in tune with the universe.
It actually could be a reason I like these forums so much. You see a guy who you think has it all together by his photos and profile and then you read his posts... and it is a reality check. Sometimes good, sometimes not so much. A couple posts have actually changed the way I view the world and my place in it. Others have made me want to drink a bottle of whiskey and then take the bottle and bash it over my head for good measure.
I guess what I am blathering on about is that I feel lonely when I am misunderstood or going through an internal struggle... not when I am in an empty house.