The English language is full of traps, making it one of the harder languages to learn. Words have two or even three meanings and depending upon their inflection or placement in a sentence, their meaning can be dramatically different. This is one reason e-mail is a challenging medium and why we have created emoticons to help get our true sentiment across.
One such word that is troublesome for me is "again".
Adding a question mark gives "again" a range of meanings, some of which express exasperation. Maybe this is why the word "again" without a question mark can also carry a tone that conveys impatience or even condescension.
Consider this: When someone doesn't understand what you're trying to say, or maybe wants to challenge you, starting your reply with "again", as in the example below, can feel a bit aggressive.
1st person: "What did you mean when you said "soon"?
2nd person: "Again, I did not say anything that would imply immediacy. I simply tried to estimate a timeframe."
Inserting "again" at the beginning gives the response a little edge, something like, "OK dummy, apparently you didn't understand what I said the first time" or "How many times do I need to say this so that you will understand?" Not always, but often times this is what I hear.
I think the use of "again" to help with clarification isn't necessary and can sometimes create a bit of defensiveness in the listener. Do you agree with this or am I too sensitive?