I must be lucky in the places I go to. A good performance from anyone is met with rapturous applause and all sorts of other appreciative noises. Personally whenever I get the chance if I've enjoyed somebody's performance I will tell them even if it's only the next time I see them.

And yes if that lady stands up with her mobile phone and scrolls up and down and loses her place several times singing the same verses over and over a song that everybody else knows backwards anyway I will still applaud politely at the end, because that's who we are!