A couple of days ago, someone raised this question.
To be more accurate, she raised it in the context of 'What's wrong about mentioning Astrology in a date'. She asked that after some guy said that he is sick and tired of people asking him what his zodiac sign is.
Well, what's wrong about Astrology really? I'll give you my (as a man, though this opinion's relevance is probably unisex) opinion:
First of all, you don't have to be a bimbo in order to believe in Astrology. It's not a necessary condition.
True, most bimbo's believe in Astrology, but that's only because the low IQ typical of superstitious belief characterizes them.
Not everyone that believes in Astrology is necessarily mentally challenged, there are few but rare cases of people believing in it due to lack of insight and thorough thinking, which is also a problem but a different one.
The question is, as an intelligent woman, why believe in something that was examined repeatedly and found false, which is based on superstition and pseudoscience?
There's nothing about "Just interested in it" here, this isn't the sports news or the weather, this is a theory (if you can even call Astrology a theory) that claims humans taxonomize into 12 different types, and that this taxonomy is derived from birth dates, those birth dates being pretty much arbitrary, and that our lives are influenced by the stars and their energy. Yeah, sure.
Whoever reads this thing and doesn't automatically flinch from its inherent stupidity, shouldn't be surprised when she is being rejected by intelligent men, and that if those have any philosophical interest, it is more in the direction of Kant and Hegel, or if they have any biological and conscious-related interest, it is more in the direction of Dawkins and Dennett. To be honest, one doesn't have to be an avid philosophy reader (I certainly can't define myself as one) in order to rule out Astrology as (and forgive me for my rudeness) idiotic mumbo-jumbo and a waste of time.
If Astrology does provide us with any sort of indication, it is more of a "If the woman you are talking to believes in Astrology, end the conversation now" kind of indication.
So, coming back to the original question, what's wrong about Astrology is that, leaving a 1/1000 case, believing in it shows lack of skepticism, superficiality, lack of depth in reality's perception (well, that might fit under superficiality) and in many cases lack of education and/or lack of intelligence.
Yes, one in a ... might believe in Astrology and still turn out to be worthwhile, but the contradiction between faith in Astrology and intelligence or true thorough thinking is so monumental, that the chance for this is infinitesimal - so it is just better not to waste time.