C.S. Lewis, writing in The Screwtape Letters, said,
“The more often [a person] feels without acting, the less he will be able ever to act, and, in the long run, the less he will be able to feel.”
Feelings are certainly important, but they are never to be our guide; truth is our guide. One’s feelings can change (sometimes quite quickly), but truth never changes. For someone to be led by feelings is to lose self control, because those misleading feelings can push us to do things that we know are wrong. For example: people might feel embarrassed by atheists who shame the Church, and so they withhold the truth and deny their faith (etc.).
Furthermore, the devil loves to manipulate feelings, and he does this often. He cannot create thoughts (or anything, for that matter), but he can prompt feelings because he can remind us of things that he knows tug at our emotions. When we respond based solely on emotions, then we are opening the door to Satan and saying “c’mon in!” On the other hand, to be led by truth is to find true spiritual strength and the devil absolutely hates that. He will try to overcome it, he will try to confuse us, and he will even seek to distract us with various temptations. We should listen to our emotions (they are helpful) but never be controlled by them (because they can be in error).
We stand fast when we stop in the midst of an emotional response and ask ourselves (and God) “what is true here?” Truth, including both God’s clear commands as well as His wise precepts, is always necessary for us to perform good works, but it is also essential in those times of emotional outburst. We can look at truth and say, “is this emotion proper here?” and “how should I respond to this experience?” Do not be led astray, whether by the world, or by your own emotions; they can stop you from being obedient to God. Trust in the truth of God, now and always.