That seems to be a popular internet myth, but without much evidence:

https://en.wikipedia.org/wiki/Blood_is_thicker_than_water

Another one I've seen recently circulating on the Internet is an idea that "The customer is always right" was originally "The customer is always right, in matters of taste". Also not true.

That might be even better! Now there's no meaning other than what you, individually, choose to attribute to it.

I love living languages.

I wonder if there's a name for this phenomenon. Eggcorns aren't quite right, as they're more about mishearing a word or phrase in a way that still makes sense in context (e.g. Alzheimer's disease -> old-timers' disease). Mondegreens are about mishearing a word or phrase and substituting them for something different. Those are errors in interpreting phonic elements, but there's no misinterpretation of the words for these phrases/idioms; it's just disregarding the meaning entirely and substituting a new meaning.

A pair of examples: “bought a pig in a poke” and “let the cat out of the bag.” “Poke” is an archaic term for “bag” [0], related to “pocket.”

Apparently a common medieval scam was to try to sell a cat as a suckling pig, concealing the cat in a bag [1]. One who buys such a pig in a poke is cheated. One who lets the cat out of the bag reveals a secret too soon.

Note however that [2] argues that this etymology for lack out of the bag” is not plausible.

[0] Etymology 2, https://en.m.wiktionary.org/wiki/poke

[1] https://en.m.wikipedia.org/wiki/Pig_in_a_poke

[2] https://www.snopes.com/fact-check/let-the-cat-out-of-the-bag..., referenced from https://en.m.wikipedia.org/wiki/Letting_the_cat_out_of_the_b...

Poke means bag in Scotland. You get a poke of chips for example.

"Gangbusters" has become a sort of generic intensifier but the original phrase was something like "to come on like Gangbusters", referring to a radio show with an obnoxiously-noisy intro (it's on Youtube if you're curious). Increasingly distant metaphorical use and people falling out of familiarity with the origin of the phrase led us to modern constructions like "my tomatoes are going gangbusters!" which don't really fit with the original usage.

I am often amused and frustrated at the common institutional excuse of misbehavior being due to "a few bad apples" as though the saying were "a few bad apples are no big deal, get rid of them (or hide them elsewhere in the barrel) if anyone happens to notice them."

I've heard that "a rolling stone gathers no moss" tends to differ in sense between the UK and the US as to whether "moss" is desirable.

The few bad apples saying actually dramatically reversed meaning.

https://www.merriam-webster.com/words-at-play/one-bad-apple-...

Right, that was my point exactly.