It would be pretty easy to say this is the greatest psychological thriller of all time. The handful of movies that come close always have something a bit cartoonish to them, but what drives Taxi Driver is an unrelenting sense of disturbing realism. It's also aged well; out-there serial killers feel like freak occurrences, but unhinged, isolation-maddened, wannabe-super heroes are all over nowadays.
The Coens got off to a really good start with this one. Honestly, I think the only person whose thrillers are close to as intense as the Coen brothers' is Scorsese. Anyway, if you like scary movies and you haven't seen this, go watch it now.
The internet made me feel bad for liking this. I'm not sure why I let them influence me; the only movies the internet likes are the Dark Knight, all MCU movies, and the Star Wars franchise but none of the individual Star Wars movies.
Anyway, I'm supposed to hate this because, in the film, some characters in their 20s make an irrational decision under duress, which I am supposed to find unrealistic. I'd say this is about as good as the seventh movie in a franchise is going to get.