I don't recall where I heard this, but I have long remembered it. It went like this: We need to stop thinking of sin as the equivalent of stealing paper clips from IBM, and start thinking of sin as the equivalent of slapping your grandmother.
How we think of sin will determine how we act and the nature of our faith (or lack of it). We often take one of two approaches. The first approach is that we see the sins of others in great detail and are utterly oblivious to our own sins. Jesus warned us about this attitude: "Why do you see the speck that is in your brother's eye, but do not notice the log that is in your own eye?" (Matthew 7:3). Or again when Jesus tells the parable of the Pharisee and the tax collector:
"The Pharisee stood and prayed thus with himself, 'God, I thank thee that I am not like other men, extortioners, unjust, adulterers, or even like this tax collector. I fast twice a week, I give tithes of all that I get.' But the tax collector, standing far off, would not even lift up his eyes to heaven, but beat his breast, saying, 'God, be merciful to me a sinner!' I tell you, this man went down to his house justified rather than the other for everyone who exalts himself will be humbled, but he who humbles himself will be exalted." (Luke 18:11-14)
The second approach is that there is no sin. Pope Pius XII famously said in 1946, "The sin of the century is the loss of the sense of sin." Instead we talk about "bad choices" or psychological disorders or the idea that "what is a sin for you may not be a sin for me and vice versa." Now, certainly Catholic moral theology takes into account degree of culpability based on knowledge that a particular action is a sin and on the degree of free consent of the will to commit the sin. But if we completely relativize sin, then we are actually saying that sin does not exist.
As Michael Dubriel rightly points out, "Remove sin and you are essentially removing God from the picture--because you are admitting that it really doesn't matter if you are offending God or not" (How to Get the Most out of the Eucharist, p. 53). No wonder faith in Western culture is on the ropes; without a sense of sin, Westerners do not feel a need for God. However, Dubriel reminds us that not only do we need God, not only do we need to be aware of our sins and turn to Him, but we need to do so constantly: "... in truth, we also need to be reconciled to him [Christ] at every moment of the day" (p. 57). We can not only receive the graces of frequent Spiritual Communion, but we can benefit as well from frequent reconciliation. The Ignatian practice of the examen is based on every day, several times each day, reviewing where we have sinned and seeking God's forgiveness and strength to love God better in the future.
Certainly it is possible to be overly scrupulous about sin. But that does not seem to be the problem with the present age. Sin can actually bring us closer to God because it makes us aware of how much we need Him. So let us take our sins to our God, whose limitless mercy and grace can restore our relationship with Him.