I won't quote anyone but I think my post will be in some way adressed to all comments in this thread:
Have in mind that I hate to talk to anything and have opinion about things I don't know for real, so I am talking from my own experience if I can. Also, I am very logically oriented, and very suspicious to different forms of superstitious beliefs, no matter if they are about glass breaking curse or about taking "scientific thruths" for granted because science as only trustfull religion is always right.
First, how many times You have talked with someone that DOES know astrology very well and thinks it is a bullshit? Only people that does not have knowledge about it and are not using it as a tool think negative. Naturally, You could say that those people are just sticking to their imagination, but think again, in all other aspects of life and different interests there are people that were really into something and then are dissapointed and are dissing this thing: For instance, someone can play guitar and be into music, and then lose interest and start to fell like it all does not have a sense, like it was all just based on his dreams of becoming popular, and he stops playing. There is always someone that was dissapointed in something that he loved or was really interested in, but somehow, I have never met a person that has learned astrology and after that got opinion astrology is just imagination, and there is nothing real there. On the other hand I know some people like my friend that became astrologer because he was studying Psychology at university, and wanted to prove that Astrology can't work, but then he ended amazed at results he got when making natal charts for people he knew.
Then there are those people hating when someone is asking them about their sign, because they think the other person is making pressumptions about them, and in some way they are not treated like a unique person, but something like part of a class of people, just a simple pattern of behaviour. This is true, personal natal chart has a lot of data, and two person of the same sun sign can be quite different, one should not judge a person by sun sign. But have in mind that some people just want to know you better without any negative attitude, and this is their way to have some quick grasp of you by knowing your sun sign. I personally avoid to ask people about that except females because they don't take this negatively most of the time.
Then there is this thing with "Stars". Sorry to dissapoint you, but physical planets, real pieces of rock floating in endless vacuum of space have very little to do with horoscope and your character traits. It is hard to understand how does horosope works if you don't know a bit about holographic view at universe, often popping up in modern physics, and about K.G. Jungs theory of Synchronisity. In causal way of thinking, there is no way planet moving has to do anything with yourself. In synchronistic concept, every part of the whole is connected with other parts, and just like hologram, has part of the information. There is no differece if part is big or small, all information about whole are there. What changes is resolution naturally, you can't get sharp clear picture from a small piece of holographic pic.
What you can in synchronistic universe is to take relatively closed system, that is easy to mathematically calculate and easy enough to follow, and use it to calculate everything else against this first system. In case of Astrology, mathematical system is moving of planets around the sun. So, Astrology is just a decoding of relationships between personal microcosmos, personal universe, and solar system. Thru hundreds and even thousands of years, people in different cultures were learning how to find relationships between solar system and life of the individual. They would calculate precise astronomical data and followed lives of their fellow man collecting informations. So all that work ended as different astrological systems as we know them today. This is simplified way of explaining, have that in mind, but I hope it sheds some light on the subject, and I am struggling to explain myself in english, so I hope this has turned out right...
Also, people hate astrology because they think it is connected with idea of fixed destiny and takes their right to make their choices from them. This is not true. Personal natal chart is not telling who you are literary: It is just giving parameters, boundaries that do keep you getting outside, but are still giving you a lot of freedom to choose what you will do inside. So when you have in chart one aspect that says that person can do on their own, but other aspect telling us that person tend to get married early and be tied to a lot of people, this is not inaccuracy, but it gives a portrait of a person that is filled with different desires and is struggling with opposites in herself.
You can compare that with sailing. You can use wind to sail in every direction, except directly against the wind, but you can get to most of places, if you know how wind acts, and learn to use it. So this is what astrology is, just a tool that lets you have a better control of your life, and not enemy of freedom to choose.
Finally, there is predictive astrology. You know that stuff from papers and magazines. Well, most of the times it is rubbish. It is not personal, so it would be stupid to think that 1/12 of all population will have similar happenings in one day. There are predictive horoscopes made for one single person, based on his natal chart, but they are often innacurate too, (it would take some time to explain why, but one of the reasons is naturally a certain degree of freedom to choose) but they can give a picture of general tendentions for a person in some period, and that can have some use, but it is hardly possible to make predictions like "You will get married at September 13. 2004.".
Finally there are astrologers talking about destiny of the nation, global things and stuff, and personaly I think it is intentional bullshiting, there is to many parametters to get any accurate result about global happenings all over the planet.
Have in mind there is not a lot of people that are astrologers that really understand how it works, just like there are people working with machines they cannot build or dissasemble, and many of them are intentionally mistifying astrology, they get their money because people tend to be superstitious, and they are using it to their adventage. It would be practical to educate public about astrology, at least a bit, because in this way things are right now, astrrology is a missuse and fraud in more then 50% of cases.