Not only does being impolite take more effort than being polite;

You know, you keep saying that like you believe it. It's not true in my experience. In my experience, it takes more work to not only come up with something that works to contribute to the situation, but also figure out how to say it that won't immediately put the person off because I'm correcting them. I have to take into account their likely emotional state, and their likely resulting emotional state (making a lot of guesses along the way), and even then I could be mistaken.

In what universe is that less work, rather than more? How are you continually making your claim without simply doing the math here?

Presuming someone claimed "1 + 1 = 3", which of these two statements takes longer to construct:

• No, one plus one is two.
• Well, that may have been the way you heard it, or were taught, but let me assure you that your conclusion really isn't the case. If you examine the items "one" and "one", and put them together, say, as marks on a chalkboard, you'll find that "one" plus "one" is merely "two", not "three".

Are you actually trying to claim that the latter is always easier than the former? C'mon. Get real.

I'm happy to put the extra effort in to "be polite" when the path is obvious to me and I have the extra time. But when my time is limited, I'm going to yell "get your hand off the stove, now!", and not worry about how to phrase that so as not to damage their ego. I'd rather make a difference than be well liked (as I've said once or twice before, in here).