"Heat"? "Sparks"? There are few to come by here (perhaps only when Dr. Bill meets Sally the roommate, but that's brought to as screeching a halt as possible). Indeed, Kubrick seemed to be visually mocking the very concepts with the gauzy yellows, arctic blues, and sickly pinks that illuminate so much of the film. (The pinks in particular--try to count just the decrepit Christmas trees with those odd pink lights bleeding out of them and you'll see how prominent a role they play. Then there's the gang of toughs (from Yale!) who gaybash Dr. Harford (a pun on Harvard? maybe I need to get out more) while saying he must be playing for "the pink team." And I don't think I need to go into the other connotation of "pink.") And people looking for them missed the point entirely. So did those who complained "That's not Manhattan!" (my God, how did Kubrick not realize he was shooting on a meticulously crafted replica? Stop the press! Alert Warner Bros.!) or even more amusingly, "That's not how the rich and powerful have orgies" (I was always tempted to intone "he added knowingly" when I saw a critic kvetching about that). The point was to show a man led off the path of what he knows to be right, only to learn the lesson that what's not right is, in fact, wrong. (And for this condemnation of sexual infidelity, the film was labeled reactionary in some quarters. I found that more sad than amusing.)
It's worth noting that the source material for the film was a 1926 book called Traumnovelle--Dream Story--by writer Arthur Schnitzler. Viewers who can't get around the episodic surreality of Dr. Bill's wanderings might be well advised to view everything between the argument and the final conversation as a kind of detailed dream, one that veers slowly from would-be wet dream to full-blown nightmare. Note the dreamlike structure, with its jarring leaps from one place and time to another (this was common source of complaint against the film, but it only served to underscore the dreaminess of the narrative). Note the somnambulistic quality of Dr. Bill's wanderings. Note his dreamlike superhuman powers: the ability to get anything he wants by saying the magic words "I'm a doctor," flashing his magical 5000-megawatt smile, presenting the magical talisman known as his medical board card, and reaching into his magical bottomless wallet; the power to be irresistably attractive to anything on two legs--models, prostitutes, little girls, hotel clerks, roommates, anyone. Note that the recitation of Alice's dream is the film's central scene. Note the references to dreaming and wakefulness in the last scene. Note the title.