Most authors shy away from exclamation points because they get that if their sentence has meaning, they don't need to dumb it down by pointing it out! Also it makes the reader feel like they are being shouted at if you use them often! But then again, maybe the reader deserves it! It can also make you feel a little stupid if the author felt the need to use ! to tell you the sentence was important!
In quality writing exclamation points are primarily used in dialog to indicate tone or expression! Most of us would agree this is the correct usage! One exception is that kids books use them to show sentences that are more important or weighty than others!
While that makes sense, I also think we confuse kids with how we teach exclamation points! As a second/first grade teacher I taught some of the more basic building block types of writing lessons kids get in school! For my grade levels there were four traits we looked at on a rubric! Those traits were, Ideas/Content, Organization, Voice, and Conventions! The rubric went to 4 points total! My last district put a high emphasis on voice (and then proceeded to teach voice poorly!) Basically if they didn't have two or more exclamation points, they dropped from a 4 to a 2, which is failing!
Because, how do you know kids really meant what they wrote if they haven't thrown exclamation points like confetti all over their page?! Sometimes you could justify it back up to a 3 if you argued a bunch, but according to the rubric it was a two! So after awhile kids just started ending sentences with them! If that doesn't get adequately taught out of them later in life they won't know any better! I don't remember learning the proper usage of them until college!
You may or may not have noticed by now that all of my sentences end with an exclamation point! That is because everything I'm saying is important and noteworthy!
One other important note about exclamations is that they are much funnier if you make a long line of them and toss in a 1 here and there like you got really excited while typing them in!!!!!1!!111!
I would ask what you thought about exclamation points here but then my sentence would end in a question mark instead of this guy -->!