Some are hilarious and all (?) have an origin that made sense at the time. Sure, one could search when curious, but I believe it would be more fun to share them, discuss them, and ask about them in a discussion.

Does anyone know an origin story for "raining cats and dogs?"

My uncle used to say, "That's slicker than goose poo in pickleberry season." He didn't say poo but you get the idea. The meaning of this one is obvious and, sadly, it never occurred to me to ask where he picked this up. Is pickleberry a real fruit? How many people slid on goose poo, and for how long, before it was agreed that it was, indeed, slicker during pickleberry season?

One of my favs that I've heard after moving south is someone "having a come-apart."

I like to say 'going to heck* in a handbasket" No idea where that came from
Wiki to the rescue!
https://en.wikipedia.org/wiki/...

Just found this thread. I love sayings. How about this, tight as Dicks hatband? Who is Dick, and why is his hatband so tight? This is usually used to describe someone who's very careful with their money.

I don't know that one. But recently looked up "Bob's your uncle"

The term "raining cats and dogs" comes from the days when little cottages had dirt floors and mud walls and thatch roofs. When it rained hard the roofs would cave in, letting the cats and dogs fall through. I saw that on a PBS program about England in the very early days.

Judith, that sounds plausible!!

Tickled pink is a curious expression. Being tickled makes me mad but the expression is supposed to indicate one is really happy.

I love the one about raining cats and dogs.

The one I had read was that when it flooded in Great Britain they had to clean up the dead cats and dogs that died in the flood.

When the cat's away , the mice will play.

Good one and not hard to understand!

I forget which relative used this one Hunger is the best sauce.

And revenge is a dish best served cold.

I am as happy as a clam at high tide!

Or happy as a pig in slop!

I've got someone or they've got me "over a barrel." Does this mean performing a balancing act? In the sum context of hearing it before, it seems more often used to indicate "between a rock and a hard place" or I could use a little tweaking in the interpretation.

I think someone over a barrel has no choice or no control in the situation

Yeah, gotta choose between 2 things that are unappealing.

This puts me in mind of something I saw not that long ago, I meant to make a note of it so I could research its origination, but did not...and now I do not recall the exact usage. However, it was one character referring to another character of questionable morals saying "...he's been that way since the devil wore short trousers..." - or something very close.

"Stuck between a rock and a hard place"

Which is the same as up a creek or up ( a certain kind of) creek. A more dire situation than going to ( heck) in a handbasket.