James4:4 You adulterers! Don't you realize that friendship with the world makes you an enemy of God? I say it again: If you want to be a friend of the world, you make yourself an enemy of God. NLT
When I was a teenager, my house fellowship teacher told us about how members of a particular church separate themselves from people even to the extent of not wanting to share the same bathroom with other 'unbelieving' tenants in the same multi tenanted house. They hardly smile at people neither do they respond to greetings properly.
When the scripture said we shouldn't be friends with the world, God wasn't saying we shouldn't live in the same house or work in the same office with them. As a matter fact, heaven is the only place where we won't have contact with sinners. What the scripture was saying is that we shouldn't compromise our stand with unbelievers by reason of friendship, involvement in evil and marriage.
If you want to evangelize sinners and you are not their 'friend' I mean at surface level of greeting, chatting and day-to-day relationship, you may not win them to Christ. Any where you find yourself, it is good you allow them know your stand without being offensive. From then on, we should make plans on how we'll reach out to them effectively.
Father, I receive grace not to compromise with the world In Jesus name. Amen