Can てしまう mean 'end up' with a positive connotation?


While てしまう is how you say 'end up' when it's something regrettable, Can you
also use it to say 'end up' if it's something good and unexpected such as:

> I ended up making friends with everyone at the party

> パーティーの皆に友達を作ってしまいました。

> I ended up inventing a new recipe

> 新しいレシピを発明してしまいました。




Most websites (e.g., [this](https://www.tomojuku.com/blog/teshimau/)) seem to
explain てしまう mean **完了** or 後悔. So it can be used for something positive as
well, and if _end up_ has the connotation of regrettable results, it may not
fit.

  * 新しいレシピを発明してしまいました。

is natural. This may be a surprise, _you know what, I invented a new recipe!_.
It could be also more simply perfect, implying _finally..._

For the first sentence, a more valid translation would be

  * パーティーで全員と友達になってしまいました。

This implies positive surprise, as you wrote.

* * *

(し)ちゃった as a colloquial variant can be used in the same way as well. I believe
in [Tonari no totoro](https://en.wikipedia.org/wiki/My_Neighbor_Totoro)
somehere there was a phrase トトロに会っちゃった.

Similarly 発明しちゃいました・しちゃった or 友達になっちゃいました・なっちゃった is ok above.




Most websites (e.g., [this](https://www.tomojuku.com/blog/teshimau/)) seem to
explain てしまう mean **完了** or 後悔. So it can be used for something positive as
well, and if _end up_ has the connotation of regrettable results, it may not
fit.

  * 新しいレシピを発明してしまいました。

is natural. This may be a surprise, _you know what, I invented a new recipe!_.
It could be also more simply perfect, implying _finally..._

For the first sentence, a more valid translation would be

  * パーティーで全員と友達になってしまいました。

This implies positive surprise, as you wrote.

* * *

(し)ちゃった as a colloquial variant can be used in the same way as well. I believe
in [Tonari no totoro](https://en.wikipedia.org/wiki/My_Neighbor_Totoro)
somehere there was a phrase トトロに会っちゃった.

Similarly 発明しちゃいました・しちゃった or 友達になっちゃいました・なっちゃった is ok above.

