Drama queen: 小题大做的人 (xiǎo tí dà zuò de rén)

You must have seen people who like making a fuss over trifles, as if they are serious and shocking. How can we call such people? 

Drama queen is a person (especially a woman) who acts as though things are much worse than they really are. 

喜欢小题大做的人（特别是女性）常表现得似乎事情比实际上糟糕很多。

Drama queen is an overly dramatic person. They can turn something unimportant into a major deal. They'll blow things way out of proportion whenever the chance is given. 

他们的表现过度戏剧化。他们能把无足轻重的小事闹成大事。他们一有机会就把事态扩大化。

Conflicts and disappointments are natural side effects of the human experience, but for a certain personality type known as a "drama queen," life's little setbacks can trigger explosive emotional outbursts and other irrational behaviors. 

冲突和矛盾原本是人生体验中很自然的一面，但对于喜欢小题大做的这些人来说，生活中很小的挫折都能引发爆炸性的感情爆发，以及其他的非理性行为。

Examples: 

1. tiān a, tā kě zhēn néng zuò xiù! wǒ cóng wèi jiàn guò zhè me xiǎo tí dà zuò de.

天啊，他可真能作秀！我从未见过这么小题大做的。

God, he's such a drama queen! I've never seen such a fuss. 

2. bù guǎn zěn me shuō, wǒ bù xiǎng xiǎo tí dà zuò, suǒ yǐ wǒ jué dìng zhǐ dāng méi kàn jiàn suàn le 

不管怎么说，我不想小题大做，所以我决定只当没看见算了。

Anyway, I didn't want to make a fuss, so I decided to ignore it. 

Source: China Daily