Forgive me if I rant but to me using “colloquialisms” or catchphrases are a cheap shortcut that will eventually lead to cheap literature.
Using them in my company is a sure way to get an eye roll and if you use these terms in a story, without making the character saying them a total caricature, it will get you a terrible review, which is what you would deserve for taking shortcuts with the English language. You are a writer, so write, say it in a way that doesn't only appeal to Valley Girls and Stoners. Write for the world and avoid these phrases, among others, at ALL cost:
"I am going to REACH OUT to that person" - If you are not within arms distance of a person, you cannot "reach out" to them. You can call them, email them, make an appointment to see them somewhere, or even snail mail them If you ever get within arm’s length of them, then you can truly "reach out" to them; just make sure they want your advances.
"I can't wrap my head around that" - Perhaps if your head was wrapped around a brain you would not have this problem. This phrase is just a meaningless cliche with no basis in anatomy.
"Back in the day..." - What day? Last Tuesday? A month ago? 1899? Get specific, tell me WHAT day you are back in. I have posed these questions to people who have used this phrase when talking to me and all I got in response was stuttering inanities, which is why they must have used this phrase in the first place.
"Don't go there" - Ummmm, where is it you don't want me to go? We were having a discussion and not traveling anywhere. Do you want me to stay away from a specific place? Should I leave the room? The building? The planet?
"It's not rocket science" - That's good since we were NOT talking about ROCKETS or SCIENCE or anything remotely related to these professions. We were talking about what to have for dinner tonight.
"Push the envelope" - Well gee, I can push an envelope. Heck, I can push thousands of them all at once. Does that make me special? Do you have any idea what it is you mean to say?
"Think outside the box" - Sorry, does it look like I have a box on my head? Maybe I should talk to my barber. What box is it that you speak of? Do you have any idea?
"Chill out" - Are you referring to my Martini? I mean it is already cold. I drink them in a toast to the English language that is being slowly killed off by catchphrases like this.
"Don't throw (someone) under the bus" - This punishment should be reserved for people dumb enough to use this irritating phrase.
"It is what it is" - But what is it? Can you tell me or are you just using this idiotic throwaway phrase to tell me you are too ignorant to express yourself in words?
There are more but if I keep writing this, I will blow a gasket...