More Like This Searches - an analogy?

I'm using 'More Like This' (MLT) searches for a problem I have and I have found them to be really well suited for the types of searches I need. I need to explain how MLT searches work in a meeting and I'm after an analogy to help illustrate the idea, but this analogy is eluding me at the moment.

I've studied the documentation on MLT searches, used the _explain API to see how things are calculated and I've been through the inner workings of the BM25 algorithm.

My audience is technical, but they aren't specialists in data or search. I need something to illustrate the idea of what is going on with this type of search without having to go into all of the details. I am wondering if anyone here has any ideas? I would be grateful for any help provided!

Hi. It uses only the interesting words in a piece of text as a search.
Technically you could use all the words in a long piece of text in a search and achieve similar quality results but it would be slower. So instead we cherry-pick the rarer words because they are most highly-valued in searches anyway, being more informative. If a rare word is repeated in a text that is also a good indication that the text is about that topic.