... TO OTHER CHRISTIANS!
Here's my ill-considered overstatement of the issue: Our problem is not that we aren't telling the gospel to our pagan friends. It's that we don't tell the gospel to our Christian friends!
When's the last time you looked another Christian in the eye and said 'Mate you're a sinner. I know you have struggles, I know you're tired but, deep down you're wicked! That's your real problem. But Mate - you're clothed in the righteousness of Christ, carried on His heart before the Father, rejoiced over in the presence of the angels.'
I don't mean, When's the last time you talked about the toughness of the Christian life, or the state of the nation's morals or the soundness of certain bible teaching etc etc. I'm talking about eye-balling your brother or sister and speaking God's word direct to them - His blood was for you, you are clean!
We all struggle to muster up the courage to evangelise non-Christian friends and family. But I wonder whether a significant part of our difficulty is that we're not even used to speaking the gospel to people who should welcome it!