While some of us are well aware of the hills we're willing to die on, others only came face to face with the limits of their ability to compromise the hard way.
And often, the matters that people are unwilling to budge on will often seem petty and inconsequential to an outside observer. And after enough of these strange conflicts come our way, we may find ourselves thinking that there's no situation where there isn't some room for compromise.
But of course, that's easy to say until you find yourself on that proverbial hill. And when the person you're arguing with is suggesting something that seems unacceptable to the point of being dangerous, it becomes easier to see why so many others chose their own hills.