As I was re-watching the Xindi arc recently I stumbled upon a nice bit of continuity.
As the episode "Exile" begins it seems that Hoshi is hallucinating. Of course, we know she's not crazy. She's being contacted telepathically by an alien named Tarquin. Interestingly, Phlox tells her that for Denobulans, hallucinating is the sign of healthy mind - it's a healthy release for the subconscious. He muses that he wishes he could hallucinate rather than keeping things bottled up inside.
Ten episodes later we have "Doctor's Orders" - which mostly consists of Phlox hallucinating while the rest of the crew is in a comatose state. It seems that he isn't keeping things bottled up so much anymore.
Star Trek has never done a great job seeding story ideas early on and developing them at a later time. For example, Phlox' puffer-face-trick that comes out of nowhere in "Home," or like Daniels showing up like the proverbial Vulcan third eyelid. (If this had been Babylon 5 he would have been a recurring character from the pilot episode forward who suddenly took on a much more meaningful role.)
But here it seems - I will choose to believe - that as silly as "Doctor's Orders" may have been there was actually some planning and forethought. The Denobulan propensity for hallucination was not introduced in "Doctor's Orders" and then reverse engineered into subsequent episodes. Instead it was set-up ten episodes earlier.
If only the Temporal Cold War had been so well thought out . . .