Terezi is alternatingly civil, flirty, manipulative, derisive and outright sociopathic in her interactions. She is almost always grinning and in many panels it appears as though she is cackling madly. From her conversations with the kids, Terezi's attitude differs depending on who she is talking to: she acts helpful towards Rose, dubs them 'hatefriends' and tells her about Sburb (To be fair, according to Karkat the word for 'friend' in the troll language is the same as that for 'enemy'). This approach may be a part of her trolling of John by pretending to be helpful towards him (through insulting him a lot in the process and using a kind of angry politeness) and giving him advice that leads to his death in the alternate timeline.

After John avoids his death, Terezi seems to have since shown remorse for her actions and claimed she felt awful for 'killing' him; even helping him through the second gate into the Land of Light and Rain to earn his trust. Her trolling of Dave has been bizarre but effective, causing him to completely lose his cool. She often takes images of Earth pop-culture characters she thinks are similar to Dave and (crudely but awesomely) draws over the picture, claiming to make it look even more like him. It is worthy to note she may have an interest in Karkat Vantas. During one conversation with Terezi, John jokingly said that Karkat was "basically in love with you," and she reacted with surprise, asking him if Karkat told him that in confidence and even asking him to copy/paste the exact words, a road which John refused to go down.

She takes interest in law and justice, has studied Alternian law thoroughly and holds a particular fascination for orchestrating the demise of the wicked, although that might not be why she caused John's death. The incident might have simply been a vain effort from her point of view, because in a conversation with Davesprite, she states that she knew John wouldn't die, as she could see him alive in the future from her timeline application in Trollian, and given that she felt guilty about the way John trusted her trolling, this is most likely the case. She also has more lighthearted interests like dragons, or collecting plushies and scales to put on her walls. She has a habit of using chalks to draw on walls for use in her live-action roleplays, and later also uses them to communicate with the exiled Black Queen. Her favorite color appears to be red and she notes that it is the most delicious color, probably contributing to her attraction to Karkat and to Dave.

Terezi is very interested in other people's blood color, but that may be more out of psychotic curiosity than hierarchy. Terezi's own blood is in the tail end of blue, keeping her out of the aristocracy's conspiracy games until she's over her head in Sgrubbenings.