Kermit and Miss Piggy watch a Punch and Judy show. Miss Piggy thinks it's too violent, but Kermit defends violence in artistic expression. This exchange immediately followed by two incredibly violent scenes.
Also a bit of a Celebrity Paradox, in a way, as Kermit is defending the artistic merits of puppetry in the face of Ms. Piggy's criticism. As in, puppets arguing about puppetry.
In a movie that features incredibly well-done practical effects and, indeed, some puppetry, plus has a cameo by Frank Oz itself. This one is a whole fridge brilliance bomb.
David's restlessness during the "Bad Moon Rising" sequence isn't just hinting that the werewolf in him is growing eager to hunt; it's also an excuse for him to leave the front door of the flat open, so his quadrupedal were-form won't have to bust its way out. If it had, Alex would have been a lot more alarmed when she got home and found her door or window torn apart, rather than just David missing.
The nurse later has a religious awakening and joins the Order of St. Raymond Nonnatus; her Name in Religion? "Sister Julianne."
The pub-goers appear to all be good friends, and when we cut back to them after Jack and David have left, they've barricaded the door. It stands to reason that the pub-goers we see regularly gather at the pub on the night of the full moon for safety in numbers.
David's nightmare features him being Forced to Watch as Nazi zombies gruesomely massacre his entire family in front of him. Judging by his age, David was likely born only a generation after The Holocaust, making his nightmare that much more poignant.
Jack warns David that the "power of darkness" and the supernatural are Real After All, meaning there really are evil forces out there.
In the finale, were-David bites the head clean off a London policeman as part of the Piccadilly "disturbance". Had David not been killed just minutes later, would there have been a decapitated corpse and its talking head among the victims next time David encountered Jack?