It just came to me like a bolt of lightning. I just saw an example of a 10-year-old's use of exclamation points in a newsletter from my son's 5th grade class.
Out of twelve sentences, five are punctuated with exclamation points, three of them with multiple exclamation points.
Immaturity - cute and endearing in a ten-year-old. Not so in a grown man.
That is what grated on my nerves so badly. But I couldn't quite figure out why it bothered me so much. But now that I see that this is how a ten-year-old writes, well, my annoyance makes more sense now; where it was just intuition before, now I have an example.
(this is where I should add five exclamation points and a rolling-on-the-floor smiley, right?)
Oooo sometimes I can't resist being bad.