Such as “money can’t buy happiness” or “what doesn’t kill you makes you stronger”. Generally a false adage or something like that. All I could think of was “fallacious bumper sticker” which just sounds stupid.
“Blood is thicker than water.”
Usually said to convince someone that you should be there to help family regardless of what that family did to you. Unfortunately the full saying is “The blood of the covenant is thicker than the water of the womb”, meaning the ties you form with friends can be stronger than the family you you born into.
This is probably not true. The concept of this phrase but referring to family is probably a modern confusion. There is no clear evidence it means it was really referencing ties to friends. Although I wish it did. Here’s some further reading from others also looking for a clearer reference.
One of the biggest cliche revisionist histories I know of is “Jack of all trades, master of none; often much better than master of one.” It’s an interesting one because it’s been retconned twice.
You’ll hear people respond to first line by saying “um actually the second line of the poem totally changes the meaning.” Yes, it did change the meaning when it was added in the 21st century, 400-500 years later.
Then you’ll hear people one step closer to accuracy who correct “Jack of all trades” by reminding the speaker that it’s not a compliment because it ends with “master of none.” Except the master of none bit wasn’t used until the 18th century, and the second revision with the couplet may actually closer in meaning to the original!
The original, simple phrase “jack of all trades” was first used in that form in the 16th century, possibly as a reference to Shakespeare, and definitely as a phrase that was intentionally ambiguous about whether it should be interpreted as a compliment or insult.
https://en.wikipedia.org/wiki/Jack_of_all_trades?wprov=sfti1#Origins
‘An old wives tale’
“Fallacy” works. These are also adages, clichés, platitudes and folk wisdom, but neither really means “falsehood” per se. However, many of them just rationalize whatever: the money one is factually incorrect and exemplifies “sour grapes”, silver linings is not a bad idea but also not necessarily true, any number of things will not kill you but make you wish they had, etc.
Whoever came up with the “What doesn’t kill you makes you stronger” adage never met a person with locked-in syndrome. That’s where you’re totally paralyzed but also totally conscious. There have been patients where the doctors thought they were in a persistent coma, but they were actually going crazy trapped in their own skulls.
A Canard (French for duck) refers to something often believed to be true but isn’t.
The origin of this expression is because the French do not believe that Quebec is real.
“Canard.”
noun 1. an unfounded rumor or story. “the old canard that LA is a cultural wasteland”