I think the parent comment is mistaken. I've always heard this used as referring to exchanges of roughly equivalent things- whereas, "an eye for an eye" leans n

I think the parent comment is mistaken. I've always heard this used as referring to exchanges of roughly equivalent things- whereas, "an eye for an eye" leans negative, "tit for tat" is neither negative or positive. To me it simply suggests the idea of a balanced exchange. EDIT: The dictionary, and the historical roots of the term, seem to agree with the parent though. Maybe I'm just an optimist and never noticed the underlying connotation of violence.