I love solo hiking for 2-3 days at a stretch. On a long solo hike my sense of self shifts so that I seem to be in my body and in the surroundings at the same time. Very hard to explain if you haven't had that experience, but there's nothing like it.
Alto said it well.
I see this is an older thread, resurrected.
I have backpacked on Sierra clubs outings, local backpack groups outings, scouts with my kids, friends, and solo, for many many years. Each has its pitfalls and rewards, and all are different.
Solo hiking goes through stages, very much like what I think yoga or meditation must give you. The first evening is a little weird - should I be doing this, am I in over my head, what if this, what if that, what is that noise, what if I am low on water, what what what. Then you replay what you would say if you were with someone else who asked this of you, and it all seems logical. The first morning is peaceful, yet anticipatory. From then on out, although alone, there is a sense of wonderment and freedom that is well worth any minimal risk that may come from being alone (except for extreme locations of course). Maybe I am showing my age, but that absolutely stupid and banal and devoid of musicality line in the Simon & Garfunkel song ".. I got no deeds to do, no promises to keep, ...." is crystal clear. Rather than loneliness, you realize how much all that is waiting for you is so important, yet that is what enables you to be out there - by yourself, yet not alone. The love of a wife, children, home, whatever is important to you - all waiting for you... but here is a chance to be a part of something much, much bigger. Steve Martin used to do a dumb skit about equating getting high with "feeling small" - well, I like that feeling of small - when you are in the middle of the desert at sunset after a very hard day ( or the AT, or the ozark Trail, or whatever), that feeling of "small" is inspiring - you come back grounded, knowing your place in the world ain't near as important as it seemed three days ago when you were at work with a tie chocking you while staring at that stupid pc monitor, but yet you know that you are part of something way bigger. It is peaceful, and should be experienced by all. Very humbling. I try for it as often as I can, but lucky if I can do 2 x a yr......