Luke 10:16 shows that one way to slam the door shut on Christ is to look at the men giving the messages rather than the God who is behind them: "My followers, whoever listens to you is listening to me. Anyone who says 'No' to you is saying 'No' to me. And anyone who says 'No' to me is really saying 'No' to the one who sent me" (Contemporary English Version).
If we believe in how minutely God is involved in our lives, then it follows that what is preached in Sabbath services has a purpose and is allowed by the Sovereign God. Therefore, a complaint that we have about a speaker or the message is a complaint against God. Despising the spiritual food God has prepared is dangerous ground to tread.
This does not mean the speaker is infallible, by any means, but the wrong attitude effectively diminishes what we can glean from his message. A safer approach would be to offer a prayer for help to understand and see how the food is for our good (Psalm 84:11) rather than to slam the door on the message or the messenger. Either we trust and have faith in God's sovereignty and His love for us, or we do not. There is no safe middle ground (Deuteronomy 30:19).