Why have I never mastered the trick of not responding to bullies?

You should respond, but respond by bullying back. Make fun of his mum, or how fat he is, or how his parent don't love him.

45 , mmm bad age to be bullied , just punch there lights out , then they will respect you . Or if your like me and fight dirty , on quick knee in the groin works .

You're 45, and STILL are getting bullied. I'm not even gonna troll. That's just sad.

I learned early on that the bullies are never prepared for the lightning attack. I found that as soon as a bully came up to me trying to start something I'd punch him hard in the 3rd button area of his shirt. When he bends and starts gasping for breath the 2nd punch would be aimed square at the nose. Now he's having trouble catching his breath, and his eyes are watering and his nose is dripping blood, he has already lost the fight, and I can punch or kick him as much as I want to. It does not take many confrontations like that to make bullies decide to pick on somebody easier. My grandpa always told me that it's always better to have more "lightning in your hand and less thunder in your mouth" 

Anecdotally, I did master the trick by being too depressed to give a ****, and I was still harassed. That whole piece of advice just places the blame onto the victim and makes them take responsibility for the bully's actions. Assuming you're young, you should get your parents to berate your school's administration until they do something for once.

If your responses satisfy you why worry about non-responses? Ignoring someone is not necessarily better. Sometimes a good response is just the right thing.

NOT IN CONTROL OF YOUR EMOTIONS AND TOO EASILY TRIGGERED.