Why do you put periods at the end of your senetence?

[Facepook]

I've always wondered this, is it a sign to show that your annoyed?

Like in pvp, some pvper put periods at the end of every post. Example, you say ”Go” to someone and they say ”Go.”, does that mean that they just don't want to battle with you, or are they annoyed with you?

Usually when I'm pvping, I like battling the same people over and over again, but soon after a few battles, they will start to put periods at the end, thats when I stop calling to them

I try to fray away from putting periods in my posts, they look at bit intimadating if you use them in a certain way. So I'm just wondering, if you put periods at the end of your senetences, whats the meaning of you doing so?

A pvper in game told me when I asked him, that it's ”correct punctuation”, but I think he uses them when he gets a bit annoyed

So if you use periods marks in pvp, or forums, why so?