I'm "slow," but it's not really that I take a lot of time with each shot. I'm a street shooter and a rapid one, but my problem is that I don't take back-up shots. I really should. I find I get lucky far more often than not, but the 2-3 scenes I shoot per day purposefully could easily be 9-12 frames total if I just wanted to be sure I didn't get motion shake, or blinking, or miss some other quick awesome moment that happened as I was putting the camera away thinking I already got what I wanted. Instead of taking a week or more to finish a roll of street shots, I could be finished in 2 days.
Although I shoot a lot of people, I find I only shoot a large amount of frames if I KNOW the people. Family, friends, documentary subjects can be the subject of a couple rolls within a couple hours. I think the difference is that I know the optimal way these people should look and I also know their quirky weird moments that perhaps I want to catch. When shooting strangers (either on the street or new people I meet while traveling) I am generally satisifed with a couple frames (but again, I think I should up that--I have SUCH a hoard of film that I really should be blowing through).
Another reason I'm a slow shooter though, is that I simply don't "go out shooting." I'm very much a "this is my life" kind of photographer. I shoot as part of my commute, I shoot in my neighborhood, I shoot in Chinatown when I'm shopping, or the neighborhood where my darkroom is, etc. Other than aforementioned times of hanging out with friends, family, or documenting something in particular, I just have several different cameras loaded with different films, and try to bring at least one with me each day...but sometimes I don't. And even when I do, I may not find a lot that day worth photographing.