People remember the favor differently when one remembers the cost and the other remembers the relief.

Two honest memories of the same act can barely overlap. Whoever gave the help recalls the afternoon lost, the awkward phone call and the money that never came back; whoever received it recalls being rescued, often without details, because they were busy being in trouble at the time. Neither is keeping score dishonestly. They stored different halves of one event.

If an old favour sits awkwardly between you and somebody, say your half plainly and ask for theirs. If you were helped and never quite acknowledged it, do so now. It is rarely too late.