Sometimes it's a matter of not having taste for it. If you give me multiple bottles of alcohol drinks, I might be able to distinguish them, but I have no clue at all which ones are supposed to be good. To me it's all just alcohol. Same with coffee - but not the same for steak.

Or perhaps they've only had good coffee, so they should try some instant coffee past its use-by date to compare.

Here's an obligatory Tom Scott + James Hoffmann episode:

I don't like coffee. Can James Hoffmann change that? https://www.youtube.com/watch?v=Z-iNAyu-ejo