Saying you use two spaces after a period tends to date you. Older folks tend to adhere to this rule, not having been taught that the only reason to do so was because in the old printer/typewriter days, every character took up the same amount of space, and so you needed two spaces after a period to improve readability and more clearly mark the end of a sentence and the start of the next. I used to use two spaces because I'm old enough that I learned to type on a typewriter and my first computer printer was a daisy wheel.
But now, of course, I'm strictly a "one space after a period guy," and you should be two. Computers do all the heavy lifting and do the kerning for you, so putting two spaces after a period looks odd, as if you're trying to pad the page count of a term paper. A good test is to pick up any book and look at the text--it's all one space after the period.
A longstanding debate in the world of usage is that of the phrase "begging the question". The most common usage these days is in the sense of "inviting the obvious question to be asked." But that is an erroneous use of the term which descends from a logic concept first formulated in a book by Aristotle.
begging the question does not mean "evading the issue" or "inviting the obvious questions," as some mistakenly believe. The proper meaning of begging the question is "basing a conclusion on an assumption that is as much in need of proof or demonstration as the conclusion itself." The formal name for this logical fallacy is Petitio principii. Following are two classic examples: "Reasonable people are those who think and reason intelligently." (This statement begs the question, "What does it mean to think and reason intelligently?")/ "Life begins at conception, which is defined as the beginning of life."
The larger issue here is whether to just accept this common misuse since most English speakers understand the intent of the usage, even if it's incorrect.
I tend to be particular about usage, and I try to adhere to the recommendations of usage gods like Garner. At the same time, I do take into account intent when interpreting the writing or speech of others.
For example, I differentiate between the kid on the playground in second grade who called me an Oriental to try to get a rise out of me from the grandmother of a friend of mine who once asked me what type of Oriental I was. That word is generally considered racially charged nowadays, but some people missed that memo and still just use it broadly to refer to things from Asian countries.
So I didn't take offense at my friend's grandmother's question. But, with a smile, I still filled her in on the sensitivity around the term. I couldn't help myself.
As for the kid on the playground, he got the reaction he wanted. I beat him up.