It says of Rehoboam that “he did evil because he did not direct his heart to seek the Lord.” So much of what we do or do not do, especially what may have eternal significance, depends on where our heart is directed. The Judgment of God, at least as it is recorded in Matthew 25, says nothing about our hearts, but only speaks of actions. And yet it is the direction of our hearts that determines our actions. It is important to note that when the Son of Man explains his judgment to the sheep and the goats, neither (those who did good and those who did evil) knew what He was talking about. Neither was conscious of doing good or doing evil: it was just what they did.
In fact I will be so bold as to suggest that for most of us figuring out what is good or evil in many circumstances is quite difficult. It is often impossible for us to discern good from evil—except in obvious matters, but even then many an adulterer or murder has said, “It seemed right at the time,” or “I couldn’t help myself.” But if our hearts are directed to seek the Lord, then we will just do good and eschew evil. It just happens, and often there is very little choosing or discerning involved: we’ve already made the choice to direct our heart towards the Lord. Everything else follows.
Sometimes (especially young people) experience a lot of anxiety about what they should do. This takes all sorts of forms from anxiety about career and marriage to fear that they may make (or may have made) mistakes along the way and destroyed God’s plan for their life. This fear is based on the misconception that God’s plan for one’s life is sort of a blueprint of where they will live, what they will do and who they will meet. While God knows all of these things (He knows everything that will happen), God’s plan is not a matter of such things. God’s plan for everyone’s life it exactly the same: that they become like His Son, Jesus Christ. Where and how and doing what are not very important. What is important is that our hearts are directed to seek the Lord.
I often quote the words of the Prophet Samuel to people: “Do whatever your hand finds to do, for God is with you.” If our hearts are directed to seek the Lord, God is with us. Keep in mind, however, that this is not an individualistic matter. While each person’s life is unique, those whose hearts are directed to seek the Lord are connected to the Lord and to each other in the Church, the Lord’s body. No one of us has all the answers for his or her own life (much less the lives of others!). One who seeks the Lord is humble and submits to wise counsel from trusted loved ones and wise elders (as Rehoboam didn’t). Nevertheless, the teaching of the Church is that doing good or evil actually has very little to do with specific choices we make (our ability to discern just isn't that good) but almost everything to do with where we direct our hearts.