Ok this is something I've been wanting to discuss! It has to do with the photo I'm going to post in here. I had been feeling really uncomfortable with this photo then I saw "Eyes for Lies" (a human lie detector I follow on Facebook) analyze this photo and how she sees fear and anguish in his face. That is the same sense I get as well and have seen others on FB posting these same thoughts (pardon if it's been discussed here before, kind of late getting over here to post).
That combined with the fact he was SITTING in the shower and Arias said he was very concerned with his privacy in the shower and for once I got a sense that little part was her telling the truth about something (which of course could be totally wrong). It's not normal for a person to sit in the shower as you say, it's awkward, water spraying in your face and hard to get back up.
My thought is that at that point she already had a weapon on him at that point and was in control of him, making him sit down, etc. It seems the shower door is closed in that photo and was open in the other ones. She also creepily pointed out to Flores how much she was enamored with that photo (no matter how you look at that,it was taken SECONDS before she started stabbing him). I could see her romantically reliving that moment as in it, she for once,had complete control in the relationship. Where is Hal Lightman when we need him?
Here's the photo you've all seen a gazillion times but ...thoughts?