Personal hygiene is something many people take care of, but don't think much of it. If only evangelism were the same way... Evangelism should be something so routine for Christians it should be like brushing our teeth and washing our hands. Sadly, it's the opposite, and so are the results.
In my years of cooking, I've had food safety drilled into my head to the point where I can ace the Serve Safe test without trouble. One thing everyone teaches is that basic preventive measures can keep a lot of trouble at bay. Basic actions like washing your hands after going to the bathroom, touching your face, touching raw meat or taking out the garbage can stop the spread of disease very easily.
Sometimes there are things we do without thinking, like scratching our nose and not washing our hands afterward. First of all, people notice little things like that and are grossed out by it. Therefore simple hygiene mishaps can lead to a poor perception of who you are. Seriously, being labeled as a nose-picker is something you don't want following you around. Especially if you want to be known for good things.
A bad impression of you may not seem like much, but think for a moment the real consequences of neglecting to wash your hands after scratching your nose. Whatever you touch now has your germs on it, which means everyone who touches those things are at risk of getting sick by you. Not only that, but a person with a compromised immune system can potentially die from getting sick. It may seem a little extreme to say this, but can you seriously live with the thought of someone dying because you didn't wash your hands?
Likewise, for evangelism, we need to represent Christ properly. Everything we do will represent Christ to the world whether we want it to or not.
D.L. Moody once said,
"Where one man reads the Bible, a hundred read you and me."
Jesus made it clear in His Great Commission to go and preach the Gospel. (Mark 16:15) Which means if we say Jesus is Lord over our lives, yet we choose to not share the Gospel, we're telling the world that Jesus isn't to be taken seriously.
Perhaps you're afraid to share your faith for fear of misleading people. Trust me, to NOT share your faith will mislead plenty of people. Think about this for a few minutes: Everyone who dies in their sin without Jesus as their Savior will stand before God at the Throne of Judgment. We as Christians, who have been bought and paid for by the blood of Jesus, are likely to faint at the sight of the Glorified Lord. How much more terrifying will it be when a sinner who cursed God all their life stands before the Glorified Christ?
"It is a fearful thing to fall into the hands of the living God." (Hebrews 10:31)
The Lord is so holy that sin has ETERNAL consequences. Sin must be punished by an eternity in HELL, a place of constant torment where a man would do absolutely anything for a drop of water on his tongue to ease his torment. (Luke 16:19-31) Tell me, can you live with the thought that there are people going there right now because they've never had the Gospel shared with them? And it's all because you're afraid to look bad? Don't blame God for people going there, He commanded US to go out and spread the message.
He wants us to preach the Gospel to the world because He DOESN'T WANT PEOPLE GOING TO HELL!!!
Sin is the most contagious disease the world has ever dealt with and it has a 100% mortality rate. Sharing the message of repentance and faith in Jesus Christ will cause people to think about their sin, if only for a moment. That's because in that moment they're thinking about their sin, they won't be sinning! Congratulations! You've slowed the spread of sin for a moment! If you keep it up, sin will slow down in people's lives and one day you'll see someone coming to repentance. Until then, sharing the Gospel will give everyone around you another chance at salvation.
"Let your speech always be with grace, seasoned with salt, that you may know how you ought to answer each one." Colossians 4:6