As far as Ariana is concerned, I just can't watch her for too long
Might I suggest listening to music instead of watching it? I think you're doing it wrong....
I would also suggest listening to music, but Arianne Grande isn't music.
Its computer generated, mass produced crap.
They mime their concerts because the song people hear on the radio (or spotify or any other service) is altered post production beyond the dynamic range of the human voice. There is literally no way they can replicate it live. Arianne Grande is no exception and lets face it, the only reason she's popular is because she is easy on the eyes.
I recently went to a Foo Fighters concert, Dave Grohl screwed up a line in Big Me. That's how you tell if they're faking it or not. Someone can perform a song thousands of times and still make a mistake, when their miming a recording, they never make mistakes. Not that anyone cared that Dave Grohl made a mistake, least of all Dave Grohl, it was still an awesome concert.