1) This sudden craze to use your cellphone as some fake lighter at concerts. It is a slap in the face of those classic rock fans who took time to have a lighter in their pocket for that moving guitar solo. Don’t cheapen it will some mode of communication. It makes you look lazy.
2) Self-Impossed Encores. What is the deal with musicians saying their good byes, running off stage, then running right back out to play another set? You earn an encore! You do not assume the crowd wants an encore, you dont plan on leaving your single (most of the time the only reason they come and endure the other hour of your best work) till the second encore.