Ironically enough, it is Tyrion that teaches her just how out of place she is in this land. Her homeland, as she has always called it before now. The practices of a foreigner mean little in a foreign land, but when in ones home? Foreign practices become oh so unacceptable.

Tyrion ignores and ignores and ignores, but when he can no longer ignore any longer he speaks up. Daenerys had appointed him her hand after all. That is his job, to speak up when no one else can, tell her she is going down the wrong path. Daenerys refuses to believe she is going mad. Tyrion is as foreign to her as she is to him. What else was she supposed to do with traitors and betrayers? A hand is to be listened to, not thrown in prison but Khals do not accept judgement from anyone unfettered.

He is right, and she knows this but Khal Drogo made a promise to her all those years ago and she will not make him an oathbreaker.