Her manners WERE too different, but after Dee ripped her a new one, it would explain most of what's wrong with Janeway "today", the lack of uncertainty and ferocious steeled aggressive focus. Dee thwacked the ensign in a face with a therapeutic shovel. Ensign Janeway died that day. What was born there, what left the counsellors couch then and there was an instantly transformed monster minus any empathy or human function.
In her bridge officers exam she flushed out half the crew through an airlock just to prove that she understood their point and they were assholes to think that they could manipulate her or find the roots of any conscience buried in her subconscious.