After watching a few aircraft making their approaches, you get a feel for how high the jets will be at a given point.  Any variation from this seems pretty different, even if it is not really that large.  A Korean Air A330 made its approach and it seemed noticeably lower to me.  There was a displaced threshold in operation so maybe they were aiming a bit closer to the piano keys than normal.  They didn’t do anything untoward but it did catch my attention.