you shouldn't have

Phrase

idiomatic

(idiomatic) Used to express gratitude at unnecessary generosity, especially when receiving a gift.

Japanese Meaning

不必要なほどの厚意や贈り物に対して、感謝の意と同時に恐縮感を示す慣用表現。

Wow, you shouldn't have bought me such an expensive gift; I absolutely love it, thank you so much.

わあ、そんなに高価なプレゼントを買ってくれなくてよかったのに、本当に気に入っています。どうもありがとう。

Sense（1）

(idiomatic) Used to express gratitude at unnecessary generosity, especially when receiving a gift.

What a lovely vase! You shouldn't have!