I don't know if it's because I grew up as an only child, or if it's just the way I am, but I have always enjoyed time alone. Don't get me wrong, I love hanging out with my friends...but I also enjoy being by myself. When I am by myself I can reflect on anything that has been bothering or interesting me. I can spend time on myself; journaling, listening to music, working out, or watching tv. I know that these are things that I could do with friends, but it's nice to be alone with yourself and an activity you enjoy. It provides an opportunity for self reflection and growth. With the busy lives we all live, it's nice to have some time away from it all. Some peace and quiet, and time to relax after a long day can be just what you need.
Time alone teaches you how to be good on your own. You won't find yourself always needing to do be with someone or doing something. There's nothing wrong with enjoying other people's company, but sometimes its good to be independent. You won't always be able to hang out with your friends or significant other whenever you want. There will be times when its seems as though everyone is busy, and you will have to spend some time alone.
Spending an extended amount of time by yourself doesn't make you socially awkward or loner. It just means that you are comfortable with yourself regardless of what your life looks like. This is really important because no matter what happens in your life, with work, friends, etc. you're always going to be stuck with yourself.
Getting to know yourself and who you are can be one of the greatest gifts you ever give yourself. If heaven forbid, you find yourself all alone, you won't feel completely lost. You will know who you are and what drives you. You need to be able to stay true to yourself, even when your friends aren't around to support you. Always be you, because being anyone else wouldn't be as fun.