"barrhhh" is used whenever you're lonely, angry, annoyed, happy, sad. it is a universal sound that can be used to portray pretty much any feeling depending on the tones used. it can also be used as a greeting.
if a group of ditzy girls are babbling and you want them to shut up, you can say, "barrhhh." if you are talking to someone and they sound overexcited about something, you can say, "barrhhh." if you're happy that you're going to eat good food, you can say, "barrhhh."