Abigail was necessary to move Shawn along. Otherwise he never becomes "Serious Shawn" and gets overheard by Juliet. All in all, though a bit tumultuous, I've liked how they've handled moving these characters forward. Juliet especially has had some rocky moments since Mr. Yin's kidnapping, so it all is working towards a good territory here, but they've wisely left some potholes in the road to navigate around.
Must say my favorite small touch of the episode was Juliet hinting that she's on to Shawn's facade of being psychic when she questions him about the three plates. I don't think when Shawn eventually reveals to Juliet that he's just really observant and not psychic that it will be a true "reveal" to her. She's figuring it out on her own. The question is how they will handle her accepting Shawn for owning up and being truthful. In any case, just blurting it out like Declan did may be something she can respect, but it wouldn't be Shawn's best choice since they've known each other for years. It'll have to come out more "naturally", if you will. Not sure how to do that, but I'm sure the writers will figure it out.
In any case, the fact that she understands that he covers for Declan by lying to her about the plates shows that while she may value truth she actually values those with loyalty more, since "lies" are not really the things people have a problem with, but rather the deception that comes with lies that are meant to conceal sincerity or some form/act of betrayal. Shawn may play the psychic, but it's to enable his sincerity and ability to help others, not to hinder or back stab. Overhearing Shawn's admission that her being with Declan was "killing him" and then having him give his blessing because he valued her happiness more than his own is exactly the quality one wants in a partner.
All that being said, the show's major strength continues to be the awesome banter between Shawn and Gus. "Maybe she's dressing you with her eyes. Ever think about that?" 
