People were drawn to Jesus because of His compassion, love, purity, wisdom, etc. He did not act like a moral policeman, pointing out sins and errors. Instead, he would talk about the uplifting and beautiful. People were encouraged, blessed by His words.
In work situations, we do not need to join every conversation. We can be quiet. "Let your words be few," Ecclesiastes 5:2. Your peaceful Christian character shines throughout your life – not only through your words. Matthew 7:16-17 (NLT), "You can identify them by their fruit, that is, by the way they act. Can you pick grapes from thorn bushes, or figs from thistles? A good tree produces good fruit, and a bad tree produces bad fruit."
However, if people are gossiping or speaking poorly of others, then it would be wise to physically step away from the group. Walking away sends a strong message. "Blessed is the one who does not walk in step with the wicked or stand in the way that sinners take or sit in the company of mockers," Psalm 1:1 (NIV).
People loved Jesus because they knew they could trust Him. By watching your words, you will develop a reputation of a trustworthy, understanding person – not a back-stabbing gossip or a know-it-all. Any mature Christian "must have a good reputation with outsiders, so that he will not fall into disgrace," 1 Timothy 3:7 (NIV).
Finally, "Let your speech always be with grace, as though seasoned with salt, so that you will know how you should respond to each person," Colossians 4:6 (NASB). It takes time to learn how to speak with grace. So, ask God to teach you. "If any of you lacks wisdom, you should ask God, who gives generously to all without finding fault, and it will be given to you," James 1:5 (NIV).