With the variety of MB-type tests on the Internet these days, it's not uncommon to have different results from different tests. The actual Myers-Briggs test is quite lengthy and involves a fair bit of introspection before settling on one's "type". If any of you are still interested in playing around with this theory, a couple of suggestions:
First the MB theory is all about PREFERENCE, which can be quite different than what you actually do in a particular situation. Mo's example of working 20+ years in a bar is a good example; because her job requires interacting with people, most observers would probably see her (and she might see herself) as having many of the extroversion qualities. To draw a parallel with handedness, it would be the same as if her job required her to work constantly with her left hand even if her preference was to use her right hand. Eventually she would become so good at using her left hand, it might seem to an observer, and even to her, that she was indeed left handed. As we get older, it becomes harder and harder for most of us to distinguish between what we can do and what we might prefer if there were no constraints on us. That's why some people think their "type" changes as they get older or they change careers.
The second thing to keep in mind is that not everyone has a strong preference on each of the scales. The characteristics ascribed to each letter are usually most accurate for individuals who are at the far ends of the spectrum, not near the midpoint. So, to use MaryK as an example, if she is near the middle of the N/S spectrum she might be much more flexible in her information-gathering strategies than someone who is near either of the ends. She is "ambidextrous" and can switch between both hands quite easily.
Last thought, I keep trying to think about how type would influence my fashion and shopping choices. Personally, I think that human behavior is dependent on so many factors, it would be hard to separate out my MB type as being the main influence on my behavior. For example, as an introvert, it would seem logical that I'd prefer to shop alone, but that behavior might also be just logical for an extrovert who has limited time and resources for shopping or who would prefer to engage in other activities with people. It's a fun way to explore possible differences but I wouldn't read too much into it.
ETA: I feel like such a downer, but I get a bit conflicted when I see how MB type theory gets so distorted on the web. The "take this quicky test and slap a label on yourself and others" approach bothers me. People are complicated and most of us can't be summed up in a four letter code. But I think recognizing that another person can have a very different approach forces us to confront that our preferences are just that--our preferences. And to communicate with each other, we have to acknowledge these differences if we want to understand each other.