Why Astrology is not reliable?

First, the fact that I decide my future, my actions are leading to a target. I am not predestined.
Secondly to see in the future is not something practical, as we see with binoculars. Time, at least for us humans follow a line: from beginning to end, from the present to one future date. Past when we relate to what we refer to an action already took place and when we refer to the future we report something that will take place in the future, but as the future is beyond the 'now, we can only relate to the future as a possible place in the future.
There the man can see beyond the "horizon" of this, the future is far away, beyond our sight.
The fact that we are certain prophecies Bible, is another story. Prophecy is the direct intervention of God, and as God is man, not subject to time ... it's a different story.
Could the movement of planets or stars influence our future? Perhaps, in a very little, very small, so small that not even deserve to take into account.
That the magnetic force of the moon or other planets have some impact on humans does not mean that the future can be predicted. People have certain inclinations, certain predispositions, and only a very small extent they can be influenced by the planets. But even so, hence to consider that:

Virgo

Today you will receive a visit from an old friend.

Let's face it. Everything is an illusion, a trick that most people accept it as science or pseudoscience.