Ha! It serves you right!

哈！你活该！

《牛津词典》

Left you, did she? It serves you right for being so selfish.

她离开了你，是吗？那你活该—你太自私了。

《牛津词典》

I also learned some useful sentences like "It's a piece of cake" or "It serves you right".

我还学到了一些有用的句子，比如“这是小菜一碟”或“你罪有应得”。

youdao

So I wrote to them and said what the western press are writing about you now but it serves you right because you are so rude - a responsible journalist asks to come into your country and you completely ignore him so you deserve all you get.

BBC: Bill Hamilton on Albania

If you take meds for the right reasons, it serves a purpose.

CNN: STORY HIGHLIGHTS