Mother Theresa said, "Without mistakes, there is no forgiveness. Without forgiveness, there is no love."
What happens when we make mistakes? Take the example of a drug addict. They spend years abusing drugs, their lives unraveling, hurting people, blowing thousands of dollars, getting arrested, etc. They want to get clean. They sweat and struggle and with support and grace and a lot of willpower, they put drugs behind them. Withdrawal is painful; not a day goes by when they don't feel like going back to drugs. They spend years repaying their debts, earning back trust. They are proud of their accomplishment, looking back on the horror and chaos of their former life and are grateful for their new life of sobriety. Life never felt so good. But every day is a struggle to stay above water. The return to grace is spent just getting back to zero.
Now compare them to someone who chose never got into drugs in the first place. They know nothing of the struggle to maintain sobriety, because they never lost it. They were able to focus their efforts on other things, maybe get ahead in life more. Drugs might have been fun, but this was a fun they never took part in. Short term "pain" for long term gain. They wonder what all the fuss is about, someone whose biggest accomplishment in life is not doing drugs.
Is the person who never abused drugs better than the one who chose to? No. But they also saved themselves a lot of grief and trouble by making the choice not to abuse drugs in the first place. The addict has had his fun, and now he is paying for it (and he knows he has to pay for it). The non-addict has nothing to pay, and so he is free to apply his efforts elsewhere.
The long hard fall from grace, though, seems to have some merit, since Jesus said, "those who are forgiven little, love little." Look at the parable of the prodigal son. The eldest son did everything right, the younger did everything wrong. The father loves them just the same, not one more than the other. But the eldest son is spiteful, and in the end, the younger brother got the fattened calf and party. The eldest son complains why he never got one before while he was doing all the right things. The father replies, "all I have is yours."
Maybe it is a matter of appreciation. Sometimes you don't know how delicious food tastes until you haven't had any for a day or two, for "hunger is the sweetest sauce." Should one take the invitation to sin, then, in order to experience the intoxicating joy of redemption--or in other words, "should we continue in sin so that grace may abound?" Paul says "certainly not!"
"When you were slaves to sin, you were free from the control of righteousness. What benefit did you reap at that time from the things you are now ashamed of? Those things result in death! But now that you have been set free from sin and have become slaves to God, the benefit you reap leads to holiness, and the result is eternal life. For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord."
One thing I worry about in our society is that things that people should be "ashamed of," as Paul says, people are not seeing as sinful. It is one thing to sin and know you are a sinner in need of grace; but things have been diluted, and people sin while not thinking themselves sinners, or even worse, that their sins are something to be proud of. This thinking will lead to death in the end, and people will say "Lord! Lord!" on the Last Day, but they will not be let in to the kingdom.
Our moral conscience is like a delicate barometric machine that needs to be finely and wisely tuned. Allowing our societal standards to inform our conscience is like letting the plumber work on your car. How do expect it to turn out--plumbers are not car mechanics! In this way I think Christ's Church serves a valuable function--helping to inform our consciences in the right way--like a lighthouse guiding ships in the dark. Without it, we are crashing our ships into the rocks, one after the other.