When we first met Juvia, she seemed pretty emotionless. Her face was secluded from everyone, even her own guild members and her voice was slow, deep, and had something depressing on it.  After joining Fairy Tail, she finally can open herself to others which made her overall a happier person. These positive emotions have come a little bit out of control if it comes to Gray.

Like all Fairy Tail guildmates, she cares very deeply about her mates. That is an effect of the other because they had accepted Juvia right from the start and didn't feared her or hated her for being before a member of Phantom Lord. For unknown reasons, Juvia tends to speak of herself in the third person and is shy when it comes to her body - as she doesn't like to shower with other girls. This shyness gets a bit lost at the year X792, where she knows has adopted (willingly or unconsciously) the habit of shedding her clothes from Gray.