Growing up in a conservative Babtist family, all they ever told us was how to convert someone, how to bring up religion in everyday conversations, etc. I was worried all my friends at school would go to Hell. I was convinced Catholics, Muslims, Buddist were all going to Hell and it was my job to get them on "God's side"
Greenfork, pay attention to the world you live in!! Its all around us!!
Indeed, Christians are supposed to "make disciples of all nations". So you could argue that Christians who keep to themselves, instead of trying to convert everyone, are in fact sinning.
You could also argue that living a life true to Christ's word is more likely to positively influence non-believers into living a godly life than is "throwing religion in someone's face" like your baptist friends did.