A friend alerted me to an article by R. T. Kendall called 'God Told Me' . . . Really? that says something I've thought for a long time but have never been able to put into words. Kendall is talking about tendency of evangelicals in general (and charismatics in particular) to say "God told me" when they think they have received some sort of message from the Lord.
There are many reasons why this is a bad idea, not the least of which being that just because you think you have a message from the Lord doesn't mean it's anything other than your own idea. Now that idea (or thought or insight) might in itself be true and good. Or it might be a useful consideration. But that's not the same thing as "Thus saith the Lord."