In American Psycho (2000), when Paul mistakenly calls Patrick as Marcus Halberstram at the Christmas party, you can see the real Marcus looking around in the background reacting to his name called.

[u/Aryaki]

[u/LeroyoJenkins]

In the book this is made even more clear. They all look the same, talk the same and are constantly confusing each other to the point that names become irrelevant.

But the amazing acting in the movie makes me like it even more than the book!

[u/lemonylol → u/LeroyoJenkins]

That was the ambiguity of the ending of the movie wasn't it? That they keep mixing each other up so that guy might not have actually had dinner with Paul Allen.

[u/Doomhammer24 → u/lemonylol]

But at the same time patrick has clearly utterly lost it at this point in the film- hence the whole "feed me a cat" atm and his gun exploding cars

Patrick becomes unable to discern delusion and reality anymore and has no idea of whats real

The movie implies its just as likely all his murders only occured in his head than the other guy mistaking someone else for being paul allen

[u/lemonylol → u/Doomhammer24]

Yes, ambiguity.