Viewing their workplace as their "mission field" causes many Christians to (sooner or later, in one way or another) evangelize at their place of employment. If you're a Christian who evangelizes at work, please take seriously the possibility that you are:
1. A bad employee. Unless part of your job description reads, "Evangelize to your co-workers," you are effectively stealing from your employer when you spend company time doing that. Worse, you are making your employer vulnerable to all kinds of trouble it does not want. As one Human Resources expert succinctly put it: "Religion, like politics, is a workplace topic that is guaranteed to generate an HR shit storm." Show your employer some real Christian love by ceasing to evangelize at your workplace.
2. Violating Jesus' Great Commandment. Jesus said that the greatest law of all -- what he himself called the Great Commandment -- was to love your neighbor as you love yourself. Trying to convert a coworker isn't loving them; it's disrespecting them, since it's asserting that you know better than they do what's best for them. And a love without respect (and remember, we're talking about your peers here) is no love at all. At best it's patronizing.
3. Violating Jesus' Great Commandment again. The odds are outstanding that once a co-worker becomes aware that you're itching to evangelize them, they'll start avoiding you like the plague. And that guarantees that you will fall out of relationship with them. And that means that you will no longer be able to in any real way love them, since you can't love someone with whom you have no relationship at all. Thus did you blantantly violate the Great Commandment.
4. Being wildly condescending. Fueling your will to evangelize is the conviction that your spiritual life is better -- richer, more rewarding, truer -- than is your co-worker's. But you have no right to in any way say or communicate that. Unless you have taken the time to become very good friends with the co-worker you're endeavoring to convert (and if you have, then why are you having this conversation at work?), you don't know them. You don't know the full extent of what they believe, or why, or how they came to their beliefs, or what those beliefs have meant to them in their life. You have no idea what their spiritual life means to them. But you can bet they have one -- or serious ideas about why they don't. And you can bet that their beliefs and convictions mean every bit as much to them as yours do to you. Respect that. Learn from it, even.
5. Out of order. Evangelizing Christians are fond of saying that they're "witnessing" to others. What they forget, however, is that the entire point of being a witness is to answer questions when asked. And only when asked.
6. Wasting your time. Evangelizing in the workplace is like evangelizing anywhere else: it doesn't work. Churches consistently rank evangelism and outreach as their top priority. In the few minutes I tried I couldn't find a more recent statistic, but a 2002 report among Protestant pastors indicated that in that year Christian churches would raise and spend more than FIFTY BILLION DOLLARS on domestic ministry. Yet today America is less Christian than ever. This is failure on an epic level.
7. Being exceptionally anachronistic. The whole idea of evangelizing is grounded in what men (not, notably, as in the case of the Great Commandment, Jesus) decided to call The Great Commission, which is when Jesus tells his disciples to "Go and make disciples of all nations" -- to get out there, in other words, and evangelize. But Jesus directed his disciples to do that at a time when just about nobody in the world had heard of him. Of course his crew had to get out there and spread the word about him. And they did! Which is awesome! It's why you yourself today have heard of Jesus and Christianity. It's why all of your co-workers have, too. Mission accomplished! You can now feel absolutely, 100 percent free to take fulfilling the Great Commission off your to-do list -- and put back on top of that list, where it belongs, fulfilling the Great Commandment.
8. Ego tripping. There's not a person in the world who doesn't get off expounding to others about why they should believe the exact same things they themselves do. It's called an ego rush. Stop getting yours at the expense of your co-workers and your employers.
9. Being emotionally dishonest. When you go into a conversation with an agenda for how that conversation should go, you're not being emotionally honest. You're not being real, spontaneous, open, vulnerable. You're not truly engaging with the other person, because at the very least you're not listening to them. What you're doing when "evangelizing" isn't a real conversation. It's a sales pitch.
10. Putting yourself ahead of God. Bringing people to God is God's job, not yours. God told you what your job is: to love others. Do your job, well-meaning Christian friend, and stop interfering with God's. I'm sure God would appreciate that, as, most certainly, would your co-workers.