没事儿找事儿的drama queen
Drama queen refers to people (mostly girls - but boys play their part) who turn something unimportant into a major deal, or who blow things way out of proportion whenever the chance is given because they either: a) want to seek attention; b) have some emotional dysfunction and it's their duty to make life harder for everyone around them; c) just simply can't get over it。
Drama queen(字面意思为“戏剧女王”)指那些(多为女性，不过也不排除男性)喜欢小题大做，一有机会就兴风作浪、夸大事态的人。他们这样做的原因有：想获得关注；情绪失控，就想闹得周围的人不得安宁；或者就是习惯这样，改不了。
由此，我们可以把drama queen译作“没事儿找事儿的人”或者“事儿妈”。
For example:
Mary blows everything out of proportion! She's such a drama queen!