Being at a loss of words is like reaching into one’s pocket at a cash register only to feel deep, vacant cloth. It can blindside you. Shake you up from top to bottom until you start foaming over.
Oftentimes people will say they can’t properly “articulate” themselves in these moments. When you can’t articulate, you need to gesticulate. Let your hand gestures do what they do best by expressing the thoughts and feelings that your vocal chords cannot.
Guitarists let their fingers do the talking. Painters lash their hands in all directions. We all fill the wordless void with some form of expression, which often involves hand gestures.
This is frustration, disappointment, and hopelessness; tensed fingers try to squeeze these feelings out of the mind.