It is an extension of it doesn't matter and I don't care. Most commonly used for inanimate objects or creatures to show indifference towards something.
Are you going to feed your fish? it doesn't care!
1) You don't care, or you don't know what to do.
2) When you really do care about something but you don't want to hurt anyone's feelings, or make them mad or something.
Boy: "So where do you want to eat?"
Girl: (really wants to eat at "McDonald's") "It doesn't matter".
Boy: "Alright, LET'S GO TO 'BURGER KING'!!!!"
Girl: (I was hoping that we could go to "McDonald's", but...ah, it's fine)
Polite thing to say when you've accidentally revealed something that's bothering you.
Used so the other person forgets about it and doesn't worry.
Person 1 - Ah, yesterday was horrible.
Person 2 - Why? What happened?
Person 1 - It doesn't matter.
Person 2 - Cool, I'm going for some chips.
Person 1: the sun will explode everything we do it pointless
Person 2: yeah it doesn't matter
Person 3: OK welp that's sad
An understated expression of a positive mood or otherwise pleasurable emotional disposition; an outcome that far exceeds the standards and/or expectations set forth prior to a defined, goal-directed behavior; an understated expression of awe at one's good fortune or that of another.
It "doesn't suck", when you have a manuscript accepted for publication in a top-tier professional journal; when you win the lottery, get a large pay raise without a proportionate raise in your job's expectations of your productivity or responsibility; getting a minimal criminal sentence rendered by judge or jury that is of far less severity thsn that which was was expected (e.g., probation versus life sentence.
The failure to so much as even achieve semantical coherence.
John, you just walked over to me like a ba'al worshipper mouth a'gape and stare blankly at me like a mad cow having a seizure - you don't even! John!..... John!!!!!! ......Does he even? *No, uh I don't think so, Sir* HE DOESN'T EVEN
Girl's definition: something that really does matter to them but they don't want to bother you with the issue.
James: How are you today
Cheyenne: It doesn't matter *sighs*
James: come on, yes it does
Cheyenne: no it doesn't... *looks down sad*
James: It's important, come on tell me
Cheyenne: Depressed
James: How are you today
Cheyenne: It doesn't matter *sighs*
James: come on, yes it does
Cheyenne: no it doesn't... *looks down sad*
James: It's important, come on tell me
Cheyenne: Depressed