A friend once had a broken tape measure; the problem was he did not know it was broken. You see, he tightened the tab on the end of the tape measure because it was loose (they are supposed to be loose!). This meant that every measurement that he made was off by a few sixteenths. He did not realize this until it was far too late on one project.
How is your "tape measure"? Not the one in the garage, the one in your heart! How do you measure the claims of others? How do you measure the things you read in the news, or the stories you hear from friends and relatives? How are you measuring this very post that you are reading? If your standard is self ("I measure things by whether I like them or not"), then your standard is broken (because we who are fallen and sinful are broken!).
We can never be a "standard" for things in that way. Only if we were immaculately conceived like the Blessed Virgin could we be used as a standard to that degree. If our only judge is "that's not what I was taught", then we are not on very solid ground. You may have been taught right and you may have been taught wrong. There is no promise of God that what you were taught is infallible. If you were taught correctly then that is good, but we still must have something more solid than our own ideas and opinions.
What if we were to use the standard of the Word of God (spoken and written both) as our gauge? Think about it: you read an article about astronomy and ask yourself, "what is the Tradition of the Church about this?" You hear that a politician passed a law and you wonder, "has Scripture given us a position on that?" Or, maybe, you are reading a book by a Catholic who says something that you are certain is incorrect, and you say "I know that the Trent Catechism has something to say about that".
We know that the Scriptures are hard to understand (as we were warned by St. Peter in his second letter). Therefore we turn to the only one that God has given the authority to determine what He has said: the Church (cf. 1 Timothy 3:15). The deposit of faith that has been given to us by the Apostles, and preserved from change or corruption by the faithful Popes of 20 centuries is clear and trustworthy. As St. Augustine said: "We judge all things according to the divine truth."