Only adjacent to OP’s request are two corporate slogans that always make me do a double-take:
Target: “Expect more, pay less” – I always read this as “Expect more, get less” for some reason
The Home Depot: “You can do it, we can help” – No I can’t, and no you won’t. Or as some comedian put it, “Should they be allowed to lie twice in the span of seven words?” (Yes, they abandoned this slogan in 2009)
So, in other words, they had been issued a citation-- which can mean a bad thing, like a parking ticket, or a good thing, like a citation for bravery 
That’s like saying a cake can be a good cake or a bad cake. True, but that doesn’t bear on the word cake. A citation just means someone is called to a spot for some sort of proclamation. The proclamation may be one of guilt or one of praise, but it’s still just a “hear ye, hear ye” paper.
I’m not sure it qualifies, but the first saying that came to mind was “Bless your heart”. Though it may be said in a sincere manner, I think it’s just as often uttered with more than a little snark.
It means according to chance, not unexpected as noted by Raza. If there were two students, and an instructor says “I will pick one of you at random to give a presentation” and you were chosen, you wouldn’t say your being picked was “unexpected” would you?
At the opposite end of probability - what about winning the lottery twice in a row? It’s also completely random, but I’d hardly call it expected.
Well, words can have denotations and connotations. I was taught in High School English the difference, using the words ‘childlike’ and ‘childish’ as an example. Their denotation makes them synonyms. However, they have different connotations: ‘childlike’ is most often used to describe innocence and purity, while ‘childish’ is mostly used to describe immaturity.
The word ‘citation’ has differing connotations, good and bad; while ‘cake’ has more universally positive connotations-- one either thinks of literal, delicious cake, or of something that is metaphorically desirable and / or simple to achieve, like “that job is a piece of cake”.
I’ve always been confused by the term “hot mess”, especially regarding a person. Apparently it just means a really big mess… but isn’t calling someone “hot” a good thing? I’d expect “hot mess” to refer to someone like, I dunno, Jim Morrison, whose personal life may be a mess, but they’re still hot.
The National Endowment for the Arts once used the slogan “A great nation deserves great art.” It struck me as a bit too close to Comedy Central’s tagline for That’s My Bush!: “A brilliant man deserves a brilliant sitcom.”
of course, there can definitely be overlap. Something happening at random may or may not be unexpected, depending on the probabilities involved.
Whenever someone says “long story short”, I think of the movie Clue. Someone would say “to make a long story short… ” and the people around would say “too late”.
Grandpa Simpson: “Anyway, long story short…is an expression whose origins are complicated and rambling.”
I don’t know of any person that likes to be called fat, But it is a compliment to call a woman ‘phat’.
Related, my teenagers tell me that saying a woman’s posterior is a ‘dump truck’ is a complement, not an insult.
One I’ve never really understood is “to be over one’s skis” which is supposed to mean “to get ahead of oneself” or “to act rashly.” But in skiing, your center of mass is supposed to be over (i.e., above) your skis for greatest stability, no? I’m not a skier so maybe it makes more sense than I realize. If the phrase were “ahead of one’s skis” it would make more sense to me.
It’s not exactly an opposite interpretation as required by the OP, but the discussion of cake reminds me of the phrase “You can’t have your cake and eat it too.” When I was young, I interpreted “have cake” to mean “eat cake” (e.g., “I had a slice of cake for dessert”) so I supposed the phrase meant “you can’t eat your cake and eat it too,” which is nonsense. I was embarrassingly old when I realized it really means something along the lines of “You can’t still own the cake after having eaten it.”
“Revenge is a dish best served cold” means “you should take your time getting revenge instead of lashing out immediately,” but it’s just as easily understood as “the best way to get revenge is to be a ruthless ‘stone-cold’ badass about it.”
I’ve often heard it as being “out over your skis” meaning leaning too far forward, i.e. not centered over your skis. So, you’re over anticipating and starting your turn too soon. But the more common problem in skiing is being behind the turn, i.e. in the back seat with your weight behind center. Not sure why this expression caught on.
How did it change meaning?
I’ve only ever heard it as achieving the seemingly impossible. Such as, somebody living in poverty starts his own business, and becomes successful. But how can he start a business without capital to begin with? A paradox that is metaphorically similar to pulling himself up by his own bootstraps.
That seems to me to be the same meaning.
Through hard work, dedication, and elbow grease. At least that’s what is meant by pulling yourself up by your bootstraps. Looking through the lens of American mythology, it has made the impossible possible.
You’re interpretation is more realistic and apropos of the original meaning. But the common meaning today ignores the impossible task and concentrates on self-made man.
I don’t think that’s a changed meaning. It just means achieving the impossible, but it can be used as either a mocking phrase toward a current attempt or a statement of astonishment at a past event. Like this:
“I’m going to be the first human on Mars.”
”Haha, sure. Go ahead and try to thread that needle.”
Lands on Mars
“Damn. That guy threaded the needle.”
They both meant to do something very difficult through a narrow, precise course of events. The first use is meant derisively, and the second is of disbelief, but they’re still the same meaning.
If one is using “literally” as an intensifier (and that is indeed how it is being used) one is not using it to mean “figuratively”. To use “literally” as an intensifier, one (hyperbolically) is using literally to mean literally.
Saying “I saw a mouse that was figuratively as big as a house” is using “figuratively” as a de-intensifier since one is admitting that one is only speaking figuratively when one says the mouse was as big as a house. So if you think people are using literally to mean figuratively, you are saying they are using it as a de-intensifier.
Saying “I saw a mouse that was literally as big as a house” is using “literally” as an intensifier since one is (hyperbolically) claiming the mouse was as big as a house.
You have it precisely backwards.