Are career quizzes accurate?

Can those tests and quizzes really help you find out what you want to do? When I take some, it’s still difficult to even complete them because I’m not so black and white as to think I’m good at only one of a few choices they give me. Or should I work on getting to know myself more…?

They are very vague: “Do you think before you act, or act before you think?”. I know that we all can’t be in a career that we love waking up for everyday, but how do you find out what your personality and career skills are?