So I get these moments when I think that some word just looks wrong, that it couldn't be spelled that way, look that way, mean that way. This alienation is not quite the arbitrariness of the sign, I don't think, but it's still problematic: I've had this feeling about "STOP" (though not recently), and just now with "happen". And this is one of those phenomena I class as tokens of the type "brainfart."