I've been thinking about the Zodiac. I'm a Pisces. You see, I know the description of my sign, and the descriptions of the signs of others. I have believed in this for a while but now I'm second guessing this entire concept...

It seems rather illogical to assume that every Piscean is going to act or look a particular way. It's illogical to assume this for every sign. Moreover, it's illogical to assume that you can predict the future based on the positions of the stars at the minute of your birth. My question(s) is(are):
Why believe in such a thing?
When does believing in something go to such an extreme that it influences everything you do?

I've gotten to the point where I try to guess someone's Zodiac sign based on their first impression and their appearance. Sometimes I'm right, and sometimes I'm wrong. I know the zodiac signs of almost everyone I know. It's influencing the way I interact with people.

I think it's delusional to believe in this sort of thing because in reality people are judged on their character and their character is judged on their actions and their personal beliefs. No one person is an extrovert or introverted simply because they're an Aries or a Capricorn.

So, answer me...Why do you believe in this? Moreover, when does it become a problem?