How do you prefer to give definition to the differences between the Thief and Rogue classes? That a Thief takes for themself while a Rogue takes for others? Or that a Thief takes when it benefits themself vs a Rogue taking for the benefit of another? A little bit of one and the other? Both at once or even some other way entirely? I personally like the "how and who it benefits" interpretation myself in the case of this question.
The how and who it benefits is a good answer because of the passive/active dichotomy, but it isn’t ALWAYS that easy, such as Roxy becoming invisible herself. It does work most of the time, though, it’s a tendency- Rogues are Robin Hood-esque by nature, where Thieves are way more focused on their goals.