“Mighty white of you.” I have no idea what this is supposed to convey, or what white means in context. White skin? White knight?
The first one, like “for all intensive purposes” is just another way for the speaker to let you know that they’re dumb. The second is sarcasm, suggesting that the item costs at least twice what is reasonable.
It’s supposed to be “I couldn’t care less”, meaning it’s so unimportant to you that it would be impossible for you to care any less than you already do. “I could care less” actually means the opposite - if you could care less, you must care at least a little bit.
Instead of head over heels, I generally use ass over teakettle, which makes even less sense.
It means to make sure you understand every little bit before you move on. Many people read to just get a basic idea.
It also implies that, although you read it, you didn’t understand what the person is getting at. In that context, I think it implies that the original person didn’t write very well, but doesn’t want to clarify.
I think you just whooshed a few people with this one. 
To be fair, I also don’t understand how people can say “could” instead of “couldn’t”, though.
Yeah, when first responding, I started to list exactly those things. Then I realized I was getting caught up in being pedantic and that, rather than spend the next two hours composing my post, I should just bail and stick a “similar to” in front of “schadenfreude”.
So I did. But I have to say that I appreciate you taking up the slack.
It means speaker is thanking someone, perhaps sarcastically, for displaying the allegedly noble tendencies of the white folk.
God never gives you more than you can handle. Guess that’s why no one ever commits suicide.
I hate it when people say “everything happens for a reason.”
Um…yeah. Cause and effect? Fine. But they seem to be implying that there is some sort of cosmic, ultimate reason that will make sense someday, like after you’re dead and you finally get some answers. Or something.
It’s especially obnoxious when something really terrible and tragic happens.
Actually, it’s “Missouri loves company.” It means, “Come to St. Louis.” 
I had always heard that other phrase as, “half-and-again as much.” That’s why I always mentally hear the nation’s name as “Half-and-again-istan.” Everything in Kabul costs more than you think.
I think the idea is that even people who are overwhelmed to the point of suicide could have handled their situation if they relied on God or found inner strength(something like this anyway).
Some people think it is Biblical, but the closest we have is:
I Corinthians 10:13
No temptation has seized you except what is common to man. And God is faithful; he will not let you be tempted beyond what you can bear. But when you are tempted, he will also provide a way out so that you can stand up under it.
They mean two different things, though. Head over heels means ‘really caught up in something’, like a crush on a girl. Ass over teakettle means ‘he fell over in a spectacular manner’.
Don’t teach your grandmother how to suck eggs.
Whiskey Tango Foxtrot does that mean?
“Our thoughts and prayers go out to the family of the victim…”
Shouldn’t your prayers be going to God? Why are you praying to the family of the victim?
I know someone who says:
I could care less, but why bother?
Funny, I always kind of thought of this as a sort of romantic thought, like "just think, of all the worlds that could even be imagined to be possible, this is the best one. Or when speaking of a specific instance, such as at work when things just work out in the best possible way.
Hee, I never understood this one either (your mom must be my mom’s twin, [and she really does have one] because mine says that too).
I guess it’s supposed to be sort of a backward “yes, this situation DOES suck, but bitching doesn’t help” sort of saying. But it still doesn’t make sense.
Phonetic alphabet used by pilots and the military. It means “WTF?”.
Regarding the phrase, “I could care less”. I’ve always interpreted that to mean, “I don’t give a shit about your problem, but I could probably care even less if I put some effort into it (but it’s not worth my time)”. Kind of a meta-not caring, if that makes any sense.
One edit: Quint beat me to it. (Guess I should start “reading for comprehension”, eh?)
I saw what you did there! I didn’t want to write “the Big F dash dash dash” outside of The Pit.
But what does the Grandmother suck eggs expression mean? Where did it come from? 
I always loved this twist on that one: **“What doesn’t kill me makes me stranger”. **
That limp? That involuntary eye twitch? They’re from stuff that *didn’t *kill you!