I could care less
Usually used when someone is being overly dramatic and is explaining the extreme action they are planning to do in response to a situation that they think you should care a lot about, but still somehow you don't
similar to "that's just fine with me"
Not to be confused with "that's okay"
You little brats don't appreciate one thing I do around here! I go out of my way to try to make you a nice dinner each night, and all you can do is complain! Well from now on you can just eat bologna sandwiches because I'm through!
That's okay with me
A response used towards someone who undervalues a thing bestowed upon them. They obviously do not realize the value nor the perks of the thing.
Platonic boy friend: Merry Christmas!!! What did you get?
Platonic girl friend: I got a gift from my uncle, he got me these Sennheiser headphones, HD 660 S I believe
Platonic boy friend: WTF??? Wow I am jealous lol, that's a very luxurious headset. So do you like them??
Platonic girl friend: Eh it's okay
Platonic boy friend: ..... what you do mean it's okay?!? Do you not realize how blessed you are????