The act of emo barfing is used to release pent up emotions as well as make everyone else within ear shot so depressed or overcome with the sudden onslaught of your crap that they too, feel as bad as the barfee or worse.
Emo barfing often occurs during periods of extreme drunkeness. It usually takes the form of unintelligable crying and sobbing where everyone present has no clue what the fuck is going on or why someone is so upset. Usually a total buzz kill, emo barfing can ruin a perfectly good day.
However if you are the one doing the emo barfing you usually feel a lot better as you have gotten rid of a lot of stress and now may watch all your friends struggle with your issues. Especially if you were emo barfing about philosophy and questioning life.