I just had a longer discussion with my wife about information systems she uses at work. My wife is working part-time as a book-seller for many years now and is often frustrated about the different capabilities of the search and ordering tools of different distributors. The systems have different user interfaces and different search algorithms. Especially the latter are the source of her frustration. Even though certain books are available from the distributors, the search engines produce different results. The book-seller has to know what he or she is searching for to find it. An idiocy par excellence.
If those search systems would provide a means to inquire on how those results were obtained (i.e., by providing action explanations) my wife and other users could either learn how the respective search works and to better use the search engines, or could complain about the search behaviour to the vendors. Either way, transparency provided by explanations would improve the overall performance.