Exclamation marks add emphasis to a statement, but a good exciting statement can convey a lot of emphasis without having to resort to punctuation.
A couple reasons for avoiding exclamation marks:
- Unlike Spanish, you only get the '!' at the end of the sentence. Therefore, if the reader hasn't realized by then that it's an exclamation, they'll be surprised and have to go back and re-read. So maybe you've got some tweaking to do.
- '!' loses effectiveness the more often it's used. If you've got them scattered in, even every few pages, the reader's exclamation-o-meter has time to settle back down to zero, and then the next '!' will be just as effective.
In a self-published novel I'm reviewing right now, the author really goes off the deep end with his punctuation. Any editor would have made him ratchet this down tremendously, but there seems to have been no editor involved, alas. It seems, though, that somewhere in his subconscious, the author realized that his exclamations were losing exclaimyness due to overuse. The solution? Multiply the number of !s and start throwing in some ?s, of course!
This is wrong. If you have any !!s or ?!!s in your work, destroy them immediately. This sort of thing has no place in formal writing.
It gets so bad near the climax of the book that there are paragraphs where every sentence ends in some combination of !s and ?s. It gets as bad as "?!!!" before he starts busting out the all-caps emphasis as well. Crimeny. At this point, the reader is laughing at your characters, not getting involved in their emotional state.