In this letter of St. Francis de Sales in response to one of his novices, he talks about just that! His first rule of thumb is this: feelings are good if they lead us to fulfill our duties, but evil if we merely stay in those pleasant feelings.
He uses the analogy that feelings are like “sauce” from God… we are not meant to eat the sauce only, but it encourages us to eat the solid meat!
St. Francis goes on to talk about pride, and how good feelings can help strengthen us to remain humble and lowly.
How do you respond to feelings in your life and deal with good feelings once they depart?