For me, it’s 马上, which means "immediately" or "right away." But the literal translation is actually "on the horse."
I know it historically makes sense because riding a horse was the fastest way to get things done, but I love it for the weird reason that I apply it to modern, mundane situations. It’s such a common phrase in daily life, but every single time I hear it, my brain instantly pictures someone desperately galloping furiously on horseback just to finish a normal chore. It's so amusing and even cartoonish to me.
Do you have a word you love just because it paints a bizarre mental picture, sounds or looks funny, or reminds you of something completely unrelated? It would be so fun since Chinese has so many words where the literal translation is wildly different from the actual meaning!