The Forer Effect: How well does this describe you?
You have a need for other people to like and admire you, and yet you tend to be critical of yourself. While you have some personality weaknesses you are generally able to compensate for them. You have considerable unused capacity that you have not turned to your advantage. Disciplined and self-controlled on the outside, you tend to be worrisome and insecure on the inside. At times you have serious doubts as to whether you have made the right decision or done the right thing. You prefer a certain amount of change and variety and become dissatisfied when hemmed in by restrictions and limitations. You also pride yourself as an independent thinker; and do not accept others' statements without satisfactory proof. But you have found it unwise to be too frank in revealing yourself to others. At times you are extroverted, affable, and sociable, while at other times you are introverted, wary, and reserved. Some of your aspirations tend to be rather unrealistic.
(From <a href="http://skepdic.com/forer.html">The Skeptic's Dictionary</a>.)
Most people will feel that this describes them fairly well, with of course a few exceptions where they feel that it is inaccurate. This is because it uses vague terms and two-sided descriptions... "At times X, while at other times not X" is always going to be true for almost everyone.
Often newspaper horoscopes use similarly vague terms, by saying "you will meet an important person today", or "hold off on that purchase you were going to make". We meet people all the time, and buy things all the time as well, and most people will feel that "an important person" is whoever they run into, or that "that purchase" could refer to a pair of shoes, or a new house, or whatever they're thinking about.
This, in the main, is why I do not believe in astrology. It tends to be rather vague and complimentary ("Scorpios have sharp eyes"... I love that one) and not supply any information except that you should keep doing what you're doing, or maybe not if you don't think so.
Astrology is for making people feel better...