1. the speaker may feel sorry for the recipient party, while they block your screen name and phone number. And file a restraining order. See also rejection hotline.
2. the speaker sincerely hopes that they never have to look at your face again. ever.
Ex. 2: I'm really sorry i ran over your dog and threw it into reverse several times. Anyways, we should do something sometime.
However, when the same phrase is employed by a chick, its more like a polite way to say "i'm not really interested."
Girl, "Sure, we should do something sometime."
Can often duplicitous or ambiguous, playing role as a "single" from opposite sex.
Jimmy: Not much, how are you?
Alison: I'm good, just a lil tired from school.
Jimmy: You know, we should do something sometime afterschool
Alison: Yeah, that be cool.