A great example is the “Clinton thumb”.  That hand gesture politicians make where they make a fist and hold their thumb over it when they’re speaking to make a point.


Politicians love the “Clinton thumb” because it isn’t as aggressive as pointing a finger or shaking a fist. 

However, as noted by Julia Louis-Dreyfus it makes you look like a moron.  It looks silly because it isn’t natural.  It isn’t a gesture a normal human being would make in real-life.  If it doesn’t work in normal conversation, it doesn’t work on the stage.