It's always nice to have one's own opinions reinforced, especially when it's by someone who really knows what they're talking about...
Above all, men should not arrogantly exalt themselves; they should be raised up and sent by God. He has this right as supreme Majesty. However, as I have already said, there must be sufficient evidence of a man's calling. We are to exercise discernment and not blindly accept it without due thought or consideration; for Satan's agents may constantly boast of their calling, whilst disguising their true characters, and thus deceitfully infiltrate the church. It is our duty to test all such, to see whether or not God has called them.
How can we know whether such people [bishops or prelates] are, indeed, pleasing to him? Well, firstly they need to have been appointed in a lawful way, accompanied by calling upon the name of God. Then, they need to have been selected because they possess the necessary gifts to exercise that office.... Therefore, those who wish to be known as bishops and prelates simply must teach. If they are nothing more than idols, or dumb dogs, we are obliged to reject and despise them, inasmuch as they shamefully mock God's name and profane his greatness.
John Calvin, Sermon on Galatians 1:1-2
I suspect I disagree with Calvin on the psychology of false ministers and teachers though. I know quite a few of them, and I genuinely think most of them mean well, which changes how we are to relate to them. I guess some of it is how Priscilla and Aquila dealt with Apollos in Acts 18:
Meanwhile a Jew named Apollos, a native of Alexandria, came to Ephesus. He was a learned man, with a thorough knowledge of the Scriptures. He had been instructed in the way of the Lord, and he spoke with great fervor and taught about Jesus accurately, though he knew only the baptism of John. He began to speak boldly in the synagogue. When Priscilla and Aquila heard him, they invited him to their home and explained to him the way of God more adequately.
Acts 18:24-26, NIV
I love that!