I thnk I'd just groan and sulk these days.
As a young man (late 80s?) I had a Brick Lane Special taken from outside a corner shop. I saw the wheel start to roll and leapt out of the door.
A man was on it and about to ride off. I'm afraid I caused him great pain and (to my surprise) didn't let up even when he was rolled up foetus-like on the floor. A couple of guys from a local scrapyard pulled me gently away from him ("You've done enough, mate"). All a bit surreal as they had welding masks tilted over their heads. I am little, but I think my fury was such that I gave him a thorough biffing with head, fist and boot.
The chap was in the gutter and groaning. The shop keeper asked if I wanted the Police, but I didn't. He refused payment for my goods.
When I got home, my housemates thought I'd been beaten up, as my 'felling punch' was a head butt and had opened the skin above my eye. My face and t-shirt were red with blood. To this day I am still joshed about pretending I hadn't been mugged.
The frame of the Brick Lane Special eventually cracked below the steering head on Upper Ground some months later and I stripped it for bits. I think the thief was very poorly when I left him and in my youth I was pleased to have caused that. I am more reflective now.
I do not think it is dignified for a middle-aged man to biff people - and in my case it would be comically ineffective too.