If you interrupt someone while they're talking, is it your fault because you interrupted that person's line of thought or is it the other person's fault because they never stop talking?
Don't stress about the answer, since there is no absolutely correct one. What this complicated question shows us is a valuable lesson in what can result a misunderstanding, because if you interrupt someone, that person might get upset, and if you explain it's bceause that person talks too much and you're trying to help her see that, better get out of the way. More, maybe you just overreacted because you were angry at something about your own life, which makes you in fact the culprit of this whole story (and to think you had sincere altruistic motivations about ending that conversation).
There are always at least two sides in each and every meaningful thing in life. To think otherwise would be the result of innocence and arrogance combined.