We live in a world where it's easy not to take responsibility. It seems normal to us that if we don't do something, someone else will. And so that means that it comes very easily to us to neglect the responsibility of personal evangelism. Yes, we know that evangelism is important. Yes, we want to see people saved. Yes, we agree that the church should be doing evangelism. But, it's just there that we so often put off the responsibility onto someone else. "The church" we say, should be doing evangelism. Rather than thinking of evangelism as our responsibility as Christians, we think of it as "the church's" responsibility. And rather than thinking of the church as us, we think of "the church" as some vague entity that does things by itself.
But, the church cannot evangelize unless we evangelize! The Body of Christ evangelizes as the members of the Body evangelize. If it's an important responsibility for the church, then it should be an important responsibility for the members of the church. We can't leave evangelism to "the church"; we must evangelize as the church.