Delighted to see actual pilots responding to this thread with plenty of there-but-for-the-grace-of-god stories, since the thread was in danger of being overwhelmed by the cluck-clucking nonpilots who haven't the faintest idea how easy it is to land at the wrong airport, particularly if you're operating single-pilot.
I once landed at a tower-controlled airport (Pittsburg, Kansas) thinking I was going into an uncontrolled field. Had plenty of radios aboard, but I didn't say a word, taxied back and took off. Never heard a word about it, fortunately.
Where I live, there are two runways roughly aligned east/west with each other, one at POU, the other about eight miles farther on, at SWF. Fly the VOR approach to SWF and the first thing you see inbound is that POU runway dead ahead... No surprise that a four-engine jet landed at POU some years ago and barely stopped before the no-overrun west end.