When Raven is seriously injured, she is put into another state of being, and to humans it is known as a coma, but in Raven's world it's just another way of healing her injuries.
And in doing so, she accidentally lets her emotions go; Rage, Happiness, Fear, Lust, Intelligence. The five emotions are finally free and no longer are under Raven's control, no longer trapped inside of their own little worlds.
The Titans have never really met the real Raven, only the dark, glum, and sarcastic one, do when five versions of Raven come out of nowhere dressed in different clothing, their minds are blown.
But the Titans don't know anything about the emotions, and they may cause a lot of unnecessary trouble.
Based a little on the actual movie, TV series, and comics, and btw, I've never actually seen all of them, just a few here and there. So don't hate on me, may be some Damirae moments, ;)