It's best if the dialogue can convey what needs to be expressed rather than relying on dialogue tags. It's a variation of show-don't-tell. Let me hear what the character wants, feels, or is thinking, rather than telling me.
If the dialogue tells me the character is upset, there's no reason to add more information:
- "I can't stand the way he treated me," she said.
- "I can't stand the way he treated me," she complained.
- "I can't stand the way he treated me," she complained bitterly.
It gets worse as you go down the list. Even the first "she said" is unnecessary if the reader already knows who's speaking.
One writer who practiced effective dialogue was James Cain. His dialogue is spare and direct, often with no "she said" or "he asked" at all. Because he could set up a scene well and get his characters to express themselves in vivid and powerful language, they could do all the talking.