Witnessing

I ask these questions to discuss the issues and to try to spark thought into why we do the things we do.
Why do we witness? As Christians, what is our motive for witnessing? Are we called to convince or coerce people to believe in Jesus, or are we called to just tell people about Jesus and let them make their own decisions? How do we witness? Do we go to the malls and main streets and popular places on the weekends and walk up to complete strangers and tell them that Jesus loves them and died for their sins with having no intention of ever seeing that person again? Do we go door to door and hand out Bible tracks that gives the Bible message in 2-3 paragraphs? Do we take a missions trip to another country and build houses or help with VBS or help AIDS victims? Do we sit down with our closest friends and really listen to what is bothering them and give them a shoulder to cry on if they need it? Is our purpose as Christians to convert as many people as possible to Christianity?