One of the things that I find I try to be on the guard against is abusing my office as Pastor to throw myself onto a hobby horse. I get nervous whenever a Pastor has an issue that is overly important to him. Why? Because I am to be a preacher of God's Word, not an issue monger.
What do I mean? I am a preacher and a teacher of a congregation. What do I preach and what do I teach? Do I focus on things that are hobby horses of mine, or things that my people need to learn and grow in? Do I preach things that pander to the congregation so that they feel better than other people, or do I preach law that hits home?
That pulpit pounding sermon on the dangers of abortion could be really popular - but on a Sunday when there's 3 women who could conceivably get pregnant - that's probably not the primary focus thoughts on the 5th Commandment should take. Teach it when appropriate, but it doesn't make sense to be *the* focus. I might get cheers for hammering on homosexuality, but is that the application of the 6th commandment that the folks of my congregation primarily need? Does my preaching of the law hit them, hit me - or does it make me smug for being better than those miserable sinners who do ____?
There is nothing more dangerous than a pastor who has a particular issue that he always returns to (at least in absentia of a direct reason for preaching it). It clouds and obscures the Word of God, and the whole counsel of God becomes nothing but encouragement to Pharisaical behavior.
This is one reason why I am so thankful for the Lectionary. It saves me from going onto a hobby horse of my own - even if it is one that might be appropriate. Say I think the congregation has a problem with "X" - yes, I'll preach about X. But only when it ties into the readings. On other weeks, the readings, the Word of God compels me to preach about other aspects of the Law, of Gospel, of the Christian life. And quite often, those hit and impact people in good ways which I didn't anticipate or wouldn't have expected.
Beware your hobby-horses, O pastor, lest you forget your duty of the care of souls!