Why are there so many different Christian interpretations and doctrines?

“one Lord, one faith, one baptism” (Ephesians 4:5 ). 

Today there are many church denomination all over around us,  yet there is a lot of mishaps in the body of Christ.

This is as a reason of different Christian interpretations of the word of God. And this is really cousins alot of problem. 

So why is this happening to the body of Christ after the word Paul the Apostle said in our text. 

 If all Christians have the same Bible, and the same Holy Spirit, should not Christians be able to agree?"