For example, let's take my horoscope for today from horoscope.com. It says:
Be careful -- things are not as they appear. Protect your financial investments. You may be taken advantage of by someone you least expect. You may be confused about a relationship you are involved in.
Things aren't as they appear? See what I mean about them liking to use very vague pieces of advice that could apply to, well, just about everybody? But even so, there are glaring inaccuracies, such as the following:
1) I don't have any financial investments to protect. I'm flat broke.
2) I doubt I'll be taken advantage of by anybody, since my plan is to stay in my room all day. But I'll get back to you at the end of the day about that one.
3) I'm not involved in any relationships. I don't have a girlfriend and never have. I don't even have any friends around here.

And here's my horoscope from Yahoo! Astrology:
The thoughts you've had don't mean what you think they do -- don't act on them yet.

Overview:
You're so proficient at center stage that you often find yourself burned from the spotlight when all you were really after was a nice, healthy glow. The fans are assembling. Better load up on whatever type of sunscreen seems appropriate.
The thoughts I have don't mean what I think they mean? What the hell is that supposed to mean? I honestly don't know. I think what I mean to think. That's what thinking is for.

And what is this spotlight they're talking about? In reality, I've been kind of depressed that nobody is paying any attention to me. There are no fans assembling. I'm actually pretty damn lonely.

If these things were real, I think we would be surprised at how all these different astrologers would be zeroing in on the same advice every day for the different signs. But as you can see, different astrologers come up with wildly different predictions.