Brynne is fairly friendly, particularly when she comes to trust people, and she values her friends above all else. She has close bonds with all of the Scions, though she's perhaps closer with Y'shtola than most of the others (barring G'raha, I'll get to him). She has complicated feelings about Emet-Selch, who she mistrusted during Shadowbringers - she felt sorry for him, especially towards the end, but never truly bonded with him because of the enmity between them. She had a very good rapport with Aymeric, which may have turned into a love affair if life didn't interfere. Hien was a trusted friend and great drinking buddy, and she deeply respected Gosetsu. She developed feelings for the Exarch during Shadowbringers, which only became stronger when she found out he was G'raha Tia, who she had been friendly with in the past. She hasn't declared those feelings because she fears her title as the Warrior of Light might entice him to accept her even if he doesn't feel the same. She understood Zenos, but took no particular pleasure in that because she saw in him the monster she could've become under different circumstances. She warmed up to Zero during their time together, initially finding her a little cold and off-putting, but coming to think of her as a trusted friend and ally eventually.
She also tends to remember her friendly encounters with others, brief as they may be, and is pleased if they meet again down the line.