Regarding "to sound intelligent," I've recently begun distinguishing between two forms:

1) Saying something correctly but unnecessarily complicated - for example, when a project manager says, "We do not have financial resources for that," instead of simply, "We don't have money for that," when declining a team dinner (a CFO's report is another story).

2) Saying something incorrectly - for instance, "It is really flustrating."

I've started to dislike the latter more. The former involves people who at least use correct phrases, even if they're trying too hard to impress others. The latter indicates people who simply don't read.

'Flustrated' looked to me like a potentially useful portmanteau word, and at least Merriam-Webster seems to agree, which would give some legitimacy to 'flustrating'. Whether the person you hear saying the latter had this in mind is, of course, another matter.

To give an idea of how I see it as potentially useful, there are some frustrating events which leave a person in no doubt that there's nothing they can do to remedy the situation (or that they have no choice but to put a lot of work into fixing a situation which never should have arisen), while others might leave a person in a tizzy over what to do now.

> The latter indicates people who simply don't read.

Or more charitably, their vocabulary is fine and they merely suffer from noun recall deficiency and or other issues with public speaking. I personally find myself thinking two or more equally valid ways to express a thought, then fumble, saying a mix of both.

Sort of a variant on 1) I dislike speakers that overuse "essentially" and "basically". I think their motivations vary but almost always the words can be removed without any change in meaning.