Some beginning writers weigh down their speech tags with adverbs that tell the reader what the character is feeling, although it is patently obvious from what she just said. Other writers have been taught that there should never be adverbs in speech tags at all, under any circumstances; that adverbs in speech tags are inherently wrong.
We feel there is a middle course. It is only when adverbs get into the wrong hands that things get ugly. Adverbs don’t kill dialogue; careless writers kill dialogue.
Overuse at best is needless clutter; at worst, it creates the impression that the characters are overacting, emoting like silent film stars. Still, an adverb can be exactly what a sentence needs. They can add important intonation to dialogue, or subtly convey information. “I love you, all right?” he said jokingly is miles away from “I love you, all right?” he said coldly. But avoid at all costs “I love you, all right?” he said lovingly.