Check Yourself: Are You Using These Words and Phrases Incorrectly?

It's time once again to polish up your writing! Below are a few words and phrases that people often get wrong. Misuse them among a group of friends and nobody will bat an eye. Misuse them in your professional writing and, well, your writing will simply be a shade less professional.
Per se
First, let's get the spelling clear: It's not "per say." Also, since it's a foreign-language phrase (Latin, to be specific), you might consider italicizing it. Check your style guide on that. But it's the usage that seems to be the slipperiest aspect of this phrase. Many, many people seem to think it's a synonym for "precisely" or "exactly," as in "She's not a skiing fanatic per se; she's more of a casual hobbyist." This is not correct. "Per se" means "intrinsically"; you might use it to contrast a person or thing by itself with that person or thing in a certain context or in combination with something else. For example: "Ammonia is not dangerous per se, but when mixed with bleach, it creates a deadly vapor.