Exclamation points have a place! But they should be used sparingly! They shouldn’t be found at the end of every sentence! Or even every once in a while! Even if you feel what you’re saying is important! Because that would be overdoing the point of exclamation points!
See what I mean? Too many exclamation points lessen the point they are supposed to make.
I recently edited a manuscript for a book that was quite good. My only problem with it was that the writer used too many exclamation points. I took out all but a half dozen of them, and that was in a manuscript of over 55,000 words. And I still wondered if that was too many. If those half dozen were enough that they diluted the meaning of the ones following truly important information.
There is no hard and fast rule about exclamation points. Use as many or as few as you feel is necessary. But remember that every time you use more than one in a manuscript … any manuscript, no matter how long or short … you dilute the value of the ones that truly are appropriate.