他在这件事上蛮不讲理。

He was being totally unreasonable about it.

他粗鲁到蛮不讲理的地步。

He was rude to the point of being aggressive.

他将不得不早点离开，因为他太太蛮不讲理。

He will have to leave early because his wife is so awkward.

在我们社会里，也有少数不顾公共利益、蛮不讲理、行凶犯法的人。

There are also a small number of individuals in our society who, flouting the public interest, wilfully break the law and commit crimes.