For example, if I have a read vs unread chart of my owned books, I would like to exclude books I have tagged as “husband” which are books we own that are his that I will never read. My read vs unread ratio is skewed since I track our library together, but my goal isn’t to read 100% of our owned books it is to read 100% of owned books minus “husband” books.

This could also be useful for other reasons