Personality Tests

I think it's common knowledge that personality tests typically tell you things about yourself that you already know. I just took the Kiersey tests (available here) as part of an assignment for an Organizational Communication course I'm taking this semester. There's a free mini test you can take and it told me I was a "guardian." The profile definitely fits me. I'm interested in seeing how my professor will relate this to the workplace. I'm sure there is link between certain personality types and how they handle responsibility...