LOL on the "Sorry Dan" part. Actually, it's called "going postal" for a good reason, and I bet Dan gets the connection. In an old South Philly Church-planting church we used to go to, one of our Leading Elders was a postman for his day job, as was his brother who also was with us in that church. (Teaching Elder left, so we had to hire Teaching Elders each week for service. They all came from our presbytery, and we came to know the four of them well. I'm not sure "Leading Elder" is the right word for that position, but they did much of the job that people think of when they think the word "pastor" without placing him behind the podium preaching -- the day to day job of pastor vs. Sunday pastor.) He taught us the post office only keeps those who work at 100% capacity 308 days a year. Preferably 315 days a week, since they only get five sick days a year, and will be reported if they go above two sick days. They'll be fired, if they take a sixth day.
It's so tough that man's wife gave birth, but he couldn't stay home to help her the first couple of days after giving birth. And, worse yet, she developed a life threatening goiter (it was cutting off her wind pipe and was caused by the pregnancy, so it was a tough decision whether they should operate -- which causes stress on the baby -- or wait for the baby to be born and hope it didn't cut off her ability to breathe through the rest of her pregnancy.) Yet, he had to work throughout that, and, after the pregnancy when she had her thyroid removed, he was written up for wasting a sick day. So, going postal is more accurate than you would think. Seriously a stressful job. (That and he was in charge of every single envelope or packages that traveled into or out of 19103 and 19106, which only you would know as all of Center City Philadelphia. He worked in 30th Street, so the busiest post office in Philly.)
But yeah, sometimes bullying is indifference. The bully doesn't care one way or the other about the target. But also sometimes bullying is target specific. One of my brothers is a bully. He targets female family members and targeted his ex-wife. It wasn't indifference. It's establishing himself in the pecking order, and everyone else learns to duck or incur his wrath too. The only ones who don't get that choice are the female family members. And he did that on purpose -- he lost to a brother, so stopped fighting him. The only thing that saved me was getting out and then marrying a big man. (Not saying God wasn't involved. I should have died a couple of times at my brother's hand.) The only thing that saved my sister was he had his own life by the time she came along. And the only thing that saved his ex was she was smart enough to give him everything in the divorce, (which was his goal.)
So there are more than one kind of bullies, but our answer really does come back to trusting Christ to change us to his good and to love through him in us. Otherwise, we are likely to go off the deep end in a variety of ways.