A couple of times, at moments when it made sense...

(SPOILERS) When I let Danny shoot the woman at the bandits' camp, I chose to be silent, because it came as a bit of a shock.

Never, I was worried that if I did everyone would think of me as less of a leader...or something.

There always seemed to be a better option.

I think I used it once or twice and it was in the same scene.
Where Lee and Kenny arrived at where the boats were supposed to be.
Then there obviously were no boats, and I felt like it would be kind of a dick move to say anything during that moment, because Kenny was so worked up about the boats at the time.
And when Kenny said something like "this one still might be salvageable" I just remained quiet, because the other options were not helping the situation. I don't regret staying silent during those times at all.