I would expect as much from someone like John Daly. But not Phil Mickelson.
I think the way he's always conducted himself compared to that moment today will be something he regrets for a long while.
He was clearly frustrated, but I've never seen him do something of that nature. I've never seen him "quit" on a round of golf, up until today. And as a lifelong fan of him, I just find it very disappointing.