Very illustrative of a 'decisive moment' 🙂
I've been lucky enough to get a few photos that could be classified as 'decisive moment' in that everything just clicked at the right time. But I'd personally attribute that to luck, with the person being photographed just turning their head at the right time, looking in the right direction at the right time etc.. and then myself being pleasantly surprised upon developing the photos. I wouldn't claim the success of the photos were due to any particular 'decisive moment' skill on my part, rather just being there at the right time with a bit of luck was enough..
Maybe I'll get it at a later stage though?