Horoscope is not meant to limit what can happen, but to help us understand what has happened and prepare for what will happen.
There are two extreme views of horoscope. One, held by some of those who frequent horoscope sites, is that fates are decided by horoscope and that decisions should be made based on horoscope.
In fact, horoscope has great influence on your personality. But your personality is not the only factor that decides your fate. You can overcome the shortcomings in your personality with your will power. If you do everything the way you feel like doing, you will be limited by your personality and your fate will indeed be decided by horoscope. But if you learn from others or you are pushed by yourself or other people, things can happen differently to you. Horoscope is just one factor in our life that we should examine. It is not the only factor. You can read more on this here.
The other extreme view of horoscope is held by many Christians who dismiss horoscope all together. As a result, they make the exact mistakes that are predicted by horoscope. This is because they do not learn from horoscope about the weaknesses in their personalities. They let their fates be limited by the weaknesses in their personalities. In other words, they let their fates be decided by horoscope.
To sum up, we should study horoscope to avoid making the kind of mistakes that can be predicted by horoscope, but should not make decisions based on horoscope.