The thing that most PH don't see is the after the sort or behind the trucks kind of pressure the sort manager has. When I was a PH I just showed up and moved boxes, got a workout and went home for a nap, I didn't get yelled at unless I put a hazmat down the belt which only happened once. A senior manager will through metrics down to other managers and eventually to a sort manager. Once you get past PH the pressure is really dumped on to you, the sort manager was more than likely showed a metric from distric and his boss told him to fix it. It's tough to connect the metric to the people and the daily operations. Not saying you should be a jerk to your PH, I'm actually very nice to everyone I manage. But when it comes right down to it, sometimes the stress leaks out into your mood and your PH are the first to pick up on it.