A couple of years ago at Shoreham, flying as a civvie. The runway orientation is 02/20 so lots of scope for confusion. I heard a French pilot on frequency having difficulty locating the airfield and joining the circuit for runway 20.
I called: “G-xx final 20” and heard “F-zz final 02”. I looked toward the far end of the (short,narrow) runway to see another single-engined piston heading straight towards me. I started a rather steep turn to the right and heard the tower calling: “G-xx IMMEDIATE right turn! My reply: “I’m already doing it, mate.”
Maybe not as dramatic as some examples on here but enough for me.