Especially in a culture that so roundly attacks Christians - not always without good reason - it's important for the world to see Christians as we really are, not as we often pretend to be. They need to see us as messed up, wounded, and hurting people who have found the great Hope and their ever-present source of strength.
If you were to share with your co-workers the ways in which God has walked with you through difficult, stressful times at work and in life, it might offer glimpses of how God could embolden their own lives. If they knew that you too went through seasons of doubt - wondering if all this stuff about the Son of God rising from the dead could possibly be true - but were sustained by experiencing the Holy Spirit's work in your life, imagine the impact. And of course there's no better way to shine the irresistible grace that has saved wretches like us than to be willing to open up areas of struggle - and mercy - in our own lives.
Now, I'm not fool enough to suggest you need to bare your deepest sins to co-workers who may or may not use them against you. But I have come to realize that the strongest witnesses - much like the strongest leaders - are the ones willing to give glory where glory is due.