You can believe without going to church. But that means faith becomes something individual. Many believers agree that faith has both an individual side (praying, being a good person,...) and a community side (mass, sacraments, evangelism, converting,... proselytism?).
Jesus barely talked to individuals in the gospels, he preferred talking to the 12, or even better, to large groups of people. I think christianity has a vocation for being universal. Every true christian (and probably muslim also) hopes somewhere that the whole world would one day believe in God. But except for some extremists, all agree that faith can only mean someting if it's based on free will. Forcing someone to believe is a total absurdity. Hence the stupidity of proselytism, but not of evangelism (converting).