“Absolutely”

There are a couple of ways in which you can use the word “absolutely” – it can be both an affirmation and an intensifier. So, when someone asks you a question, you could simply reply, “Absolutely.” On the other hand, you could use it to emphasise your point: “I am absolutely exhausted today!”
While it’s fine to use as an affirmation, you may want to think twice about using the word as an intensifier. Like “literally,” it can sound weak and unintelligent. Plus, it is another of the “Most Irritating Expressions in the English Language,” according to the University of Oxford.
“For all intensive purposes”

If you’ve been using this phrase since before you can remember, the chances are you haven’t a clue what it means. Many common English mistakes come from us listening and repeating what we think we hear, and “all intensive purposes” is not the correct phrase. What you mean to say here is “for all intents and purposes,” as in “for all our needs.”
“Shouldn’t of”

Somewhere along the line, people misheard the phrase “shouldn’t have” and started using “shouldn’t of” instead. It conveys a lack of understanding of the English language that really irks some listeners.