Two schools of thought surround the exclamation point. Over-eager (often newbie) writers use way too many, because they just LOVE what they're writing and they just KNOW the reader is as excited as they are about it. I recently stopped reading a book because of the author's exuberant use of EPs. It wasn't that interesting anyway, but the constant use of unnecessary EPs, sometimes two or three at a time, made it seem like the author was trying to force me to feel excitement where there wasn't any.
One of those ideas is as bad as the other.
Overuse of EPs makes writing seem immature and gushy. Using none at all
can make it dead. My position is that anything that helps the reader understand better is a
good thing. We can't sit beside readers and tell them the story, so we
have to give clues whenever possible--as long as we don't get carried
away. When Retta calls Barb at the
beginning of Captured, Escape, Repeat, her emotional state is riled. Her boyfriend just disappeared. She's been crying. She needs help. That's what exclamation points were invented to convey.
Writers use question marks, periods, commas, and lots of other punctuation marks. If we know how to use them judiciously, we should get to use them all.