Heron I see what you mean. Fi users also seem to "flex" their nose in a way. The nose, or at least the nostrils, stiffen up to add to that sort of Fi snarl. Looking at the Fe users their noses, most especially their nostrils, are at rest when smiling.
I guess this might derive from a reluctance and outward discomfort with Fi users in revealing their personalized feelings.
In theory there is a possibility of perfect happiness:
To believe in the indestructible element within one,
and not to strive towards it.