This next thought is cryptic, I know. I learned in yeshiva that a person should use his mind to govern his heart, because the heart is driven by temptation while the mind is driven by intellect.
Tonight I had to make a decision on something that came up in a thought of mine where it was the other way. My mind played tricks on me and used my beliefs about how everything always turns out good in the end, among other belief systems I have firmly planted -- but my mind used it to drive me to decide one way. My heart, on the other hand, knew the right and moral thing to do and was not sending me any signals of temptation.
The trick for me to decide when I get into scenarios like this is to look at which is tempting me with desire -- my heart or my mind? Whichever is causing the desire, that is the party that loses the case. I decide to go with the organ that is not tempting me because I trust that it is not deceiving me like the other is (who is utilizing desire, my favorite "sin", to tempt me).
Usually it is my heart that really feels the need for whatever I am seeking out at the time; my mind usually knows the logical answer that is in line with my goals. Tonight my mind used my goals as a negotiating tool to stimulate desire and urge me to side with its logic. But I knew from my beliefs that what it was telling me was dead wrong, and that going with my heart would produce the result that is in line with my goals and my beliefs.
So when the roles are flipped as they were for me tonight, and the mind is the one that was causing the desire, would it be better to have gone with the heart who knew the true answer? or would it have been better to side with the mind who had my goals' interests in mind? Here tonight I sided with my heart because here I can guarantee you my devious mind would have gotten me and others in trouble.