In my experience, and contrary to the belief of many people, I have found accountants to be very creative people. This is because they constantly have to look at things in different ways. In any sort of categorisation there is the same need for creativity. Categorisation is only a logical procedure when the categories are firmly established with the given criteria. Then it becomes boring even if useful.
Lawyers also spend a lot of time in creative categorisation.
One of the simplest of all perceptual exercises is to take eight random words and then set about dividing them into two groups of four words each. This is usually possible whatever the words might be. This is a pretty random array. This leaves the other four in the non non-living group. The others are relatively 'low energy' item.