All powers influence a parahuman's mental state. Brutes are reckless, Movers are fidgety, Shakers like to settle down somewhere. Power-induced psychosis- where a person's personality, likes, dislikes, ticks and instincts reflect their abilities in some way- are most pronounced with Thinkers and Tinkers.
Take, for example, Accord. His intellect escalates the bigger the issue he's tackling: as a result, he's barely engaged with the smaller stuff, like human lives. Think of Tattertale's need to needle people, or how Coil's actions became more and more depraved due to his ability to avoid consequences.
