"Nevertheless many even of the authorities believed in him, but for fear of the Pharisees they did not confess it, lest they should be put out of the synagogue: for they loved the praise of men more than the praise of God."
If I publicly confess my belief in Jesus, I'm not going to be thrown out of the synagogue. I have no fear of Pharisees. So what am I afraid of? Why am I so reluctant to speak openly about my faith? While it's true that I do love the praise of men, I don't get much of that as it is, and I doubt that I would get much less if I were forthright about my faith in Christ.
I think that, for me, the reticence is due to an aversion to awkwardness. It's just a fact that a lot people don't want to hear about anything remotely religious, let alone about faith in Jesus. It makes them uncomfortable. Sometimes it even makes them mad. And I don't like to make people uncomfortable or mad. (Okay, once in a while I do, but not usually.) So, for the most part, I err on the side of silence.
This policy, however, is self-inconsistent and rests on a fundamental disordering of priorities. I have faith in Christ because I believe that to know, to love, and to serve Him is the most important and life-giving thing a person can do on this earth. And I'm gonna keep my mouth shut about that because I fear a little awkwardness? Come on.