The sufferings of Christ were real, agonising and literally excruciating.  He handled them with steady resolve because of the joy of completing the salvation work (Hebrews 12:1-2).  And yet we can treat them so lightly.  His agony on the cross informs our worship and the wonderful songs we sing; they are the essence of our communion services.  But we can so easily separate them out into a 'religious' part of life, and silence their message in the workplace, home and leisure environments.  The truth is that Jesus was put to death because of our sins (1 Peter 3:18), so that we might be free to live a new life ... and not go back to old ways.
 
To ‘be done' with an old relationship means that you never return.  To ‘be done’ with exams is never to take another one. To ‘be done’ with sin is to be settled in your heart and mind that you are not going to insult the Lord Jesus by despising His painful sacrifice - by continuing to lust after the same offensive passions that took Him to the cross.  His purpose was to fulfil God's will by His obedience so that our disciplined obedience should also achieve His will.

This is the central point of Christian discipleship.  Titus 2:11-14 puts it like this: “For the grace of God has appeared that offers salvation to all people. It teaches us to say ‘No’ to ungodliness and worldly passions, and to live self-controlled, upright and godly lives in this present age, while we wait for the blessed hope – the appearing of the glory of our great God and Saviour, Jesus Christ, who gave himself for us to redeem us from all wickedness and to purify for himself a people that are his very own, eager to do what is good.”
 
But many Christians never properly think about it: they are content to use the benefits of the cross to soothe their worries while they fulfil their own ambitions.  So, Peter instructs us to take a grip of our thinking.  If we say that we follow Jesus (who was totally focussed on the Father's will), is the same true for us (Philippians 2:5-8)?  If not, these verses are an important starting point to consider what real Christian living is all about.  Then we need to make lifestyle decisions that are in line with God's purpose for us, and be accountable to other people to fulfil them.  Godly believers at work might provide just the incentive you need, and your example of repentant living might be the spur to their holiness too.