The expression "I don't care" has a long history in English. It is used in negative constructions and can be a polite way to say that you don't want something or someone. It can also be impolite and dismissive, so you should use it sparingly.
When Apocalyptica released their song I Don't Care, it quickly became an international hit. The lyrics spoke to the hearts of many music listeners, and they were able to relate to it in their own relationships. The narrator in the song is not a people person, but she can make him feel like he belongs in social situations.
In informal speech, it is common for people to switch between "I don't care" and "couldn't care less." Although grammarians and English teachers prefer the more logical "couldn't care less," there is no reason to avoid the latter when it sounds natural.
It can be difficult to know how to respond to a comment or criticism, but you should never respond with "I don't care." Instead, try using one of the alternatives in this article. And don't forget to check your work for spelling and grammar errors with LanguageTool! Your writing will be more professional, and you'll be able to prevent misunderstandings.