Think of a local church which emphasises the doctrine about all believers being members together of the Body of Christ (1Co.12:12,13). Suppose people in that church imagine that because they believe this doctrine they are the Body of Christ and no one else! Another church teaches that since the early church had only one church in any locality and it was known by that locality, e.g., the church in Corinth, we should not have different churches in the same place. But what happens when they start calling themselves the church in that locality, to the exclusion of all the others? Another church wants to be in the '144000' (Re.14:1) as a distinct group among all believers. But can someone who is in that church assume that because he accepts this doctrine he is in that number and others are not? There are many other examples!
Is spiritual qualification based on what doctrine we follow or how we live? What are we going to be judged for, our knowledge of doctrine or how we have actually lived our lives? The Bible is very clear that our judgment (evaluation or assessment) will be based on our deeds (2Co.5:10). As those who have been made children of God by His grace through our faith, there is not going to be any judgment on us (1Th.5:9) like the one the other people will face which will determine their eternal destiny (Re.20:12). Our 'judgment' will be to assess our fruit in life and ministry so as to give us rewards and responsibilities (See the parable of the talents in Mt.25).
How deceived we will be if we merely take pride in our doctrine and look down on others who do not value our doctrine as much as we think they should! Knowledge of doctrine is not to be an end or goal in itself. It should equip us to live better lives and to serve the Lord and His people better! If our life and service have not become any better, what right do we have to get excited about our doctrine? And certainly, if we have rightly understood any doctrine of God it should result in more humility in our heart which is seen in our behaviour rather than pride that looks down on others!
The basic problem is that we get taken up with some 'form' and imagine that the form is the same as spirituality. But spirituality is about an inner reality, isn't it? A correct form of doctrine can lead us to a correct experience of spirituality inside us. But it is not automatic. There is a good chance, as can be seen all around and in our own life if we are honest, that we start taking pride in our form and miss the inner development that God wants to lead us to.
Also, there are all shades of doctrines, but not all of them are equally important or capable of leading us to a godly life (1Ti.6:3). Here again let us avoid the tendency to spend too much of time on doctrines that are merely peripheral. They may add to our knowledge and give us an appearance of being scholars, but they may only make us puffed up (1Co.8:1) and not make us any more godly that we were before!