narff

Narff: A word used to express different emotions, depending on tone and context. Can express a desire for something. Can mean anything from agreement, and excitement to dissatisfaction, or disappointment. Can be in response to either good OR bad news.
Origin: Reminisent of character "Snarf" from Thundercats.

Example 1:

Kid #1: Guess what I just got for my birthday! That PSP you always wanted!

Kid #2: NARFF!*

(Aka: "That's not fair, I wanted that!"