TheInfiniteLight,
All the things that Katzpur mentioned are very important!! Some are even, what are called Cacodoxies, which mean that can cost you your life.
Here is something everyone MUST understand, the Bible does not put in one place all things that relate to any subject. There are very few scriptures that are Categoremata, or Categorematic scriptures, which means there is no other scriptures that modify or complement the scripture. Most scriptures are Syncategorematic, they can be changed or added to, modified or complemented. This is why the Bible tells us that we should search for truth as you would for hidden treasure. After all, it is very seldom that we find gold or silver just lying on the ground, in easy sight. Bible truth is the same way, we must search for truth, because over the years, by the process of syncretism, many false doctrines have been accepted into, what used to be Christianity, but is no longer. The fact is that the main foundation doctrines of all the main religions are founded on false teachings. We are now almost two thousand years since the last book of the Bible was written, and Bible writers warned that many false teachers would arise and mislead many. Consider the warning of Paul, at Acts 20:29,30. Consider also 2Tim 4:2-5, where we are told that the time was coming when people would not listen to true doctrine, but would gather together teachers who would tell them what they wanted to hear, tickle their ears. Notice what Peter wrote as a warning, 2Peter 2:1-3.
As to whether doctrines are important or not, I believe that Jesus knew the answer to that, consider John 4:23,24, where Jesus said that we MUST worship in spirit and truth. Consider again what Paul was inspired by God, to write, 2Thessalonians 2:8-13. Notice that the Bible said that people would be destroyed because they did not have a LOVE of the TRUTH.
The Apostle John warned that the vast majority would be fooled by Satan, Revelation 12:9, 1John 5:19.
Think seriously the warning of Paul, at 2Corinthians 4:3,4, and 11:13-15.
One last point, at Matthew 7:21-23, Jesus said that people would call him lord, lord, and say didn't we do all kinds of things in your name, and Jesus would say for them to get away from him, because they were workers of lawlessness.
The reason that God had His word written down, was because it is important to know the truth, 1Timothy 2:4.
If a person changes the scriptures, it is to his own destruction, 2Peter 3:15-17. Stumbling anyone is a great offense, because they could then lose out on everlasting life, Matthew 18:6,7, Philippians 1:9,10, the very ones who Christ died for, 1Corinthians 8:11, Romans 14:15.