Writing in 'First Person'

Okay, my current manuscript was going nowhere. (There, I said it) I was about thirty pages in and couldn't get comfortable with the guy running around in my head. I loved the story concept, but I wasn't feeling my main character. I'd been writing about him for weeks and still didn't know him. I was observing him, but couldn't figure out what drove the guy. I was writing in third person (which I love) but it just didn't...fit. Now that I've given first person a shot, it's as if I've slipped on a pair of warm fuzzy slippers in the middle of winter time. Suddenly his actions don't leave me second guessing myself. Anyway, 'til next time...