The part after he puts Fiona's head in the fridge and he takes the medicine and we see that he's seeing things as he wants to see them rather than in reality. I wish we hadn't seen what things really look like in his house until Lisa sees it.
I think the audience might not have understood what was going on if we hadn't had that glimpse until then. That scene showed it wasn't just things like the severed heads and animals talking that Jerry was hallucinating but rather that his whole perception of reality was "off" making him the ultimate unreliable narrator.
Several legit reviewers either wilfully avoided mentioning this point in their reviews, or were genuinely unaware that Jerry was only seeing a warm, inviting reality inside his apartment BECAUSE of the pills. Even the shrink's office is a little off in various scenes. I thought it was a very clever conceit.
And I wonder if on meds and his home looked like that, what did the bathroom factory REALLY look like?
And also the people he worked with, and or killed?
And I keep seeing the pets really turning their backs on him during his reality, they look scared of Jerry.
But the scene where Lisa is in his apartment , Mr Whiskers says nothing, and Jerry scream "No she's the best thing in my life!" Very powerful and totally underrated acting from Ryan right there.