Although feelings are important, they must be ruled by reason, which itself should be enlightened by the Faith. Unbridled feelings are a danger to the Faith because they can lead to the denial of Truth, especially concerning those truths revealed by God that are hard to hear and that may produce in us "negative" feelings.
For example, the dogma that only Catholics in state of grace go to Heaven. If we do not master our feelings, we may feel very sorry for those dear ones outside the Church who are clearly in the path to Hell, to the point of absolutely denying the dogma, instead of working towards the person's conversion.
We must bridle our feelings, less we fall into what is known as sentimentality, which is very detrimental to the Faith (take another example: the modern notions of "all you need is love and mercy without justice" behind the current moral societal leprosy). If we become too sentimental, we may be inclined to twist the clear teachings of the Church exalting human law over God's law. Unruled feelings can get diabolical very quick.