That exclamation mark told me a whole history. It told me that the programmer had had a hard time getting the file saving function to work. In alpha and beta releases the program had crashed at various points during the process. The programmer had not slept wondering what was wrong. And he wanted recognition for his work.
So when he finally got it to work, he was surprised, hence the exclamation mark. And you, the user, should be grateful that the program has done what it has been designed to do. The correct functioning of the program is so rare that it is worthy of an exclamation mark.
Neither Word not AutoCAD tell you that the file has been saved (for example). These programs do what you ask obediently, and silently. It is not a surprise that they work properly.
If you ever use a program which puts exclamation marks in its messages, do backups of your data often.
And if you write programs which put exclamation marks in messages, please stop. Though I suppose you can be forgiven if you have to tell the user:
But non life threatening messages do not warrant an exclamation mark.
Multiple exclamation marks are also bad form in writing. I once saw this at the end of a self published book:
In this case I suppose the author is asking sympathy, the book is long and took a lot of research, and look: I've finished!!!!!
Actually the book, though it told an interesting story, badly needed an editor, so the exclamation marks could be for the reader: I've finished!!!!!