Testimony and witness are important especially under difficult circumstances. Jesus' testimony, Him being the "truth" cannot be doubted. It gives confidence, encourages us and provides comfort to know that the testimony given is true.
We are afraid to be clear wittnesses as it will expose us to ridicule, being the "odd one out", behind the times. We also know that we do not always live lives revealing God's promises of peace and joy, and hence "self conscious" of our lives lest we should be confronted on these issues.