When Picard and Lily are going through the ship and the part where Picard says the Borg won't attack if they don't see them as a threat, why is that? Why are other times the Borg are on their zombie hunt to assimilate, but in that scene they weren't? Why was that time different, and how did Picard know that? Wouldn't the Borg always want to assimilate? Why wouldn't they see un-assimilated beings as threats?
The Borg only attack/assimilate a threat or target. If a drone is carrying out some other activity, then it will not drop it to attack/assimilate if it has no motivation to. Thus, you could walk through a bunch of drones, and they will ignore you and just go about your business.
If the collective determines that you have something they want,. then they will come after you to assimilate you. If you pose a threat, then they will attack you to eliminate the threat.
Note that I see the Collective as a giant mind, with the Queen as the embodiment of the conscious mind. The attack/assimilate actions are subconscious, and the Queen probably isn't aware of each act of assimilation, or of each threatening away team that is dealt with (of course, she could find out if she wanted to, but a constant influx of that much information would overload her). On occasions however, the Queen has shown a particular interest in these actions, such as her interest in assimilating Picard and Data.