There are expressions that never die out. The top expression at eslbuzz.com is:
1. I'd better get on my horse. This is an expression I've never heard anyone say. So as number 1 in the list, the my 'take-away' is that this is a very old list. These are expressions from my childhood...
2. Break a leg! Good luck! (Usually said to someone who is going to appear in front of an audience.)
3. Dig in! You can start eating your meal.
4. Bite your tongue! Keep quiet!
5. Butt out! Go away and mind your own business!
6. By the skin of my teeth. Only just.
7. Beats me. I don’t know.
8. Drop me a line. Write me (a letter).
What about current jargon? I found a list that looks more current at babble.com by JOHN-ERIK JORDAN
21. What’s up? / Wassup? / ‘sup?
Meaning: “Hello, how are you?”
No matter what you learned in English lessons, do not greet a friend or acquaintance with, “How do you do?” What’s up? or the even more informal ‘sup? mean the same thing without making you sound like you should be doffing a top hat. In more formal situations, it’s better to say, “Nice to meet you” or “Nice to see you.”
The beauty of What’s up? is that it is not really a question in need of an answer. Just like the French “ça va?” you can respond to “What’s up?” with… you guessed it: “What’s up?”!
We know you’re thinking it, so here’s the beer commercial that made the phrase world famous.
In the old days, awesome was a word reserved for the truly powerful, fear-inducing and sublime: the view from a mountaintop, the sea during a storm, the voice of God emanating from a burning bush. You know, massive, awe-inspiring things that “put the fear of God in ya.” But awesome has expanded in the American lexicon to include the less awe-inspiring, like a hit single, a hamburger, some new sneakers… if you’re even just mildly excited about something, it can be awesome:
“I saw the new Star Wars in IMAX over the weekend.”
“Awesome. Did you like it?”
“Oh yeah, it was awesome. Hey, can I get a sip of your iced tea?”
Like can be used as multiple parts of speech (comparing similar things, in similes, a synonym for “enjoy”), but it’s slang usage — introduced into youth culture by “valley girls” in the 1980s — is hard to pin down.
“Oh my god, it was like the worst date I’ve ever been on. Richard was like such a jerk!”
In this example, like could be mistaken for a preposition meaning “similar to,” but it’s actually not! When dropped into sentences in this manner, like is a discourse particle or discourse marker which denotes topic changes, reformulations, discourse planning, stressing, hedging, or back-channeling.
In practical terms, “like” is the word that just falls into the gaps in speech when you might otherwise say “um” or “uhhh.” If you want to hear like in action, there is no better example than Shoshanna from the TV show Girls. She’s like the best!
Important note: Peppering too many likes into conversation can make one sound childish and frivolous — fine for parties but probably not job interviews (but most Americans under the age of 35 say the word more often than they probably realize).
18. I hear you / I hear ya
Meaning: I empathize with your point of view
With only three words you can make it plain that you are really listening to someone and relate to what they are saying:
“I’m kinda sad to be back from vacation. I wish I was still on that sandy tropical beach.”
“I hear ya. After I got back from Acapulco, the view from my apartment depressed me for weeks.”
“Tell me about it,” is the sarcastic alternative, as in “don’t tell me about it because I already know too well!”
17. Oh my God!
This exclamation is not as pious as it sounds. In fact, conservative religious types would probably find it tasteless (not to mention that it breaks the fourth commandment!) and would likely substitute with “Oh, my goodness!” Denizens of the internet probably recognize the version of this phrase that’s become enshrined in meme-dom as “ermahgerd.”