Let's have a look at the definition of the word "Doctrine".
doc·trine [dok-trin] noun
- a particular principle, position, or policy taught or advocated, as of a religion or government: Catholic doctrines; the Monroe Doctrine.
- something that is taught; teachings collectively: religious doctrine.
- a body or system of teachings relating to a particular subject: the doctrine of the Catholic Church.
doctrine: "That which is held to be true by any person, sect, or school; especially, in religion, a tenet, or body of tenets"
"A belief or set of beliefs held and taught by a church, political party, or other group"
A Google search
If good doctrine were the most important thing, then all churches, or even all religions, should have the same doctrine. However, but the very fact that there are many thousands of "Christian" denominations, we know that isn't true. Each denomination has their own set of doctrines. If that isn't true, then why the need for all the different religions?
What it is not:
Often used like a weapon, the word "doctrine" is often bandied about to try to prove that someone else is wrong. "That's not correct doctrine!" What is meant, "you don't agree with my beliefs, so YOU are WRONG?" How prideful and arrogant is that?
In this country there is a strong emphasis on having "correct doctrine." There seems to be countless doctrines and countless varieties of those doctrines. These doctrines are what separate and divide those who should be acting as brothers.
In reality, I don't think "doctrine" is nearly as important as many religious people place on it. Most of what I've seen that has been called doctrine has just been some men or group's opinions. Then people get their pride attached to their opinions and things can get really explosive. Each person or group has to be "right". Then, when someone claims that they are right, by implication, that means that everyone else is wrong.
Instead of claiming correct doctrine, shouldn't we put our emphasis on (our) correct thinking and behavior? Jesus said, "All men will know that you are my disciples by your love for one another." That is focusing on correct thinking and behavior, not focusing on doctrine. If one's doctrine does not major on loving one another, then that doctrine should be discarded.