A show of to me is someone who cant bear to hear some one else play well.
There is a guitar player local to our area who is very good.
But he is very annoying at singarounds and open mikes because he seems to feel that if anyone else does well it somehow diminishes his own performance.
So he tends to fall of his chair or knock drinks(other peoples) over.
He is occasionally crass enough to play the same tune or song directly after someone else has performed it in order to upstage them.
I play guitar in my own amateurish way and have several times been asked to play a song only to have somemone else in the room try and put me down by making sure everyone knows they are a better player or singer.
If they knew what a waste of their time and effort this is on me they would not bother.
I know most players are more profficient than I am but I do it for enjoyment and get genuine pleasure when I play as well as I can and the audience show that they aprreciate my efforts.
Performance is great! Show offs a waste of time and tallent.