Depends. I used to be miserable if I didn't have some intimate level of companionship. My first three girlfriends used me until I had no use to them (two of them cheated on me, one with about a dozen different people) and dumped my sorry ass. Still, after each one, I found myself miserable and longing for that feeling again. Just to have someone to cuddle with, talk to, etc. which lead to each subsequent relationship ending up the same.
Now the 4th one. She was a good person. She was nice, nerdy, cute, supportive, etc. We didn't always see eye to eye, and it lead to the whole going to bed mad thing more often than I'd like (but making up was fun so whatever), but overall it was good. I had a good, loyal girl and things were looking up for me. The big problem with us was her borderline obsession with work. We lived about an hour away from each other and she rarely, if ever, had the time to see me. She had more than enough money, and transportation, but she never had the time because she worked 10 hour days at a pizza place. I didn't have nearly as many resources, but I still would have made the trip if she was ever free to take advantage of it. Long story short, the longing for physical affection got the better of me and I ended up being unfaithful and tried covering it up, and it blew up in my face.
Now, after this disaster, and what was probably 3 months of self-loathing, I was ok with being single for once. I felt like a piece of shit that didn't deserve any woman. I never thought I'd end up cheating on anyone and saw myself as as low of a human as you can be. I was ok with being single because I didn't think I deserved to be with anyone. Even if I did, at that time I was too afraid to let it happen, because I felt like a time bomb, I could do the same thing any time to any girl and I'd rather be alone forever than put anyone else through that.
A big reason I got past that was my current girlfriend. I knew her before I even met the aforementioned "good one". She was the biggest help anyone could imagine to be. She'd stay up late on school nights just so I could beat myself up over the phone to her, she'd listen to anything i had to say at any time and seemed to always know exactly how to make me feel better. She's an even longer distance than the last one (literally across the country), but I'm so in love with her. She's everything I've ever wanted and needed in my life. We're both working right now toward settling in in California (where she is) and moving back here when our schooling is finished. I'm many times happier than I can remember ever being, and I firmly believe that by far the biggest reason is her.
Short version: I'm usually miserable if not in a relationship, but sometimes it's good to stay out of the "game" and reflect and figure out what you have to offer and what you want. And sometimes it's better to be alone and content than with someone that makes you miserable. But i am currently taken and couldn't be happier about it.