Four of Cups and Five of Cups

Not noticing, then losing. The Four is apathy with a cup on offer; the Five is a cloaked figure over three spilled cups with two still standing behind him. The tradition reads the run as the cost of having been absent, and it is careful not to make that an accusation.

Associated with something ending while somebody was disengaged from it. Read as grief with regret mixed in.

An opportunity missed and then genuinely gone. Frequently read in hindsight.

Both cards contain something unregarded: an offered cup, two upright ones. That repetition is the reading, and it is the most useful thing in the pair.