Wow, that sounds eerily like 1984:
"In the Two Minutes Hate [Winston] could not help sharing in the general delirium ... Of course he chanted with the rest: it was impossible to do otherwise. To dissemble your feelings, to control your face, to do what everyone else was doing, was an instinctive reaction. But there was a space of a couple of seconds during which the expression of his eyes might conceivably have betrayed him."
Basically, if you have to do that, it means there is some implementation of thought police around you that you are hiding from.