Do you ever get that? Late yesterday evening my legs went all twitchy and wriggly and couldn't keep still. It was just before bed too, so it wasn't good timing. I walked upstairs, muttering to myself about legs that want to go out on the town while the rest of me wants to sleep, and, in this state of distraction, sat down on the toilet - to promptly fall off.
When you've been using the same toilet for 20 years you come to know what to expect. Your bottom anticipates a certain height and feel to the seat. If it doesn't find that, your whole body is thrown into turmoil. Or mine was. Hence the slight tumble.
And all because Husband left the seat up.
(And, yes, I know I've used a split infinitive but, as I've said before, when you understand the rules, you can break them.)