A concert is a really special thing. Music is the only popular art form where we can really be there and connect to the artist. When you're at a show where the band and the crowd connect you can tell it's something special. Read any interview with a popular musician and they'll tell you the same.
So let's put our phones down and listen.
A side note: this is made much better when artists offer video/audio recordings of their shows after the fact. I honestly don't get why every single artist doesn't offer to sell soundboard recordings. Jam bands (notably Phish) have been making tons of money this way. You can give everyone who came to the show a free download and let those who couldn't be there oay for it. That removes one major need people have for their phones.