I once read a story here, posted in its entirety... one of those things where you have to scroll down and down and down, and the text is going fuzzy by the end, where the author had managed to avoid using the word "said", throughout.
The dialogue itself was great, the story was excellently plotted, but I struggled to get to the end, for the simple reason that the constant exclaiming, retorting, urging, shrieking, snarling, barking, growling and sniffing distracted me so much from the dialogue itself that I stopped noticing, or even caring, what the characters were saying. These so-called "Said Bookisms" ruin good writing.
There is a very simple reason why good authors tell us to stick to "he said, she said" as much as possible. (Elmore Leonard lists this as his first rule of writing, and Stephen King has a lot to say on the subject, too. In fact, just about any book I've read on writing fiction reinforces it).
"Said" is a magic word. It becomes invisible. To a certain extent, so do "asked" and replied". Beginning writers are scared to use it, because they think if they use it all the time, their dialogue will look boring. But, if the dialogue is strong enough, you don't need to tell us how someone said something. And if you have your character doing something while they're talking, it will be obvious.
For example, compare:
"Don't leave me," she exclaimed tearfully.
She lifted up her face toward him, and slowly wiped the tears from her eyes. "Don't leave me," she said.
The worst examples of Said Bookisms are those dialogue tags which are physically impossible. For example, "he grinned". Have you ever tried grinning words, or smiling them, or even sneering them. They are all facial expressions, not ways of speaking.
Another no-no is using redundant speech tags. For instance:
"I'll get even with you," she threatened.
"Look out!" she warned.
"I'm so sorry," she said, apologetically.
I think all these things have their place, but the best writers use them sparingly. The occasional "shouted" or "muttered", or "whispered" is fine. (But "half-whispered"? I think not.) Also, it's sometimes necessary to use them when the the tone of voice is not clear from the actions or the speech itself. It's often useful when something is being said ironically or sarcastically.
He handed her the piece of paper.
"Thank you," she said.
Now, what if the piece of paper is a speeding ticket?
"Thank you," she said, miserably.
Or an overdue homework assignment, handed to a teacher.
"Thank you," she snapped.
But actually, both the examples above to could be rewritten to convey the speaker's misery or impatience by describing her body language. The speeder could bow her head, and the teacher snatch the paper out of the student's hand.
The overuse of Said Bookisms and adverbial tags tells the reader you're trying too hard, and that you don't trust the strength of your writing. And it's almost patronising to the reader, as if you're saying, you're too stupid to figure out how my character is saying these words, so I'm going to spell it out for you. It's an example of "telling", when you should be "showing".