These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Award Snub: After winning a Golden Globe for this film, it was assumed that Jim Carrey would at least get an Oscar nomination, but he didn't. Amazingly, it happened again the very next year, making one wonder what it will take for him to get some Academy love.
Just to put this in perspective, winning the Golden Globe for Best Actor in a Motion Picture Drama is a virtual guarantee of an Oscar nomination at the very least. Carrey was only the fourth man it didn't happen for, and the last time it happened prior to him was in 1965. He was also the last such snubee, indicating that the Academy really just didn't want to nominate him.
The film itself was one of the most acclaimed of 1998, yet failed to receive a Best Picture nom, despite getting nods for Peter Weir's Direction and for the Script.
Bilingual Bonus: In the background of the scence when Truman's dad is being taken away, two arcs display the words "unus pro omnibus, omnes pro uno", Latin for "One for All, All for One". Truman exists for the rest of the world's entertainment, and all of Seahaven exists for Truman. Perhaps better, Truman exists for the rest of the world's entertainment while that world cheers him on.
Hilarious in Hindsight: Truman's first love, Lauren, is removed from the show when she tries to reveal the Broken Masquerade. Just before the footage of the event is played, one of the waitresses in the Truman themed bar quips "They got rid of her, but they couldn't erase the memory."
While it satirized Reality Television right before the television market got saturated with it, The Joe Schmo Show in particular uses the same exact concept that the movie was making fun of.
He Really Can Act: Jim Carrey really spread his wings here and showed he could do more than just "zany".
In fact, Gene Siskel and Roger Ebert publicly apologized to Carrey on their show for saying that he would never have a career when Ace Ventura was panned, although the latter had already turned the corner with Carrey with positive reviews for The Mask and Liar Liar.
Similarly, the film is one of (if not the most) acclaimed of director Peter Weir's career, and retains an increased relevance today due to its accurate prediction of society's fixation on reality television.
Moral Event Horizon: Depending on who you ask, Christof had his when he had the idea for the show, when he faked the death of Truman's father in order to give the poor kid a crippling phobia about water, or when he capsized his boat and tried to drown him.
Paranoia Fuel: Particularly bad is when we see Truman's best friend, someone he has known since school, manipulating him and being fed lines by the director. Then there's the part where he's looking for Truman and has childish "hide-and-seek" lines delivered in sinister fashion.
More broadly, the fact that if you've seen this movie, you will wonder if your life could be a similar scenario for at least a passing moment, here and there.
The Truman Show delusion is a documented psychiatric condition, often afflicting those with schizophrenia. It is so-called because many who report the delusion specifically relate their lives to the film.
Values Resonance: There was a time when this movie's premise seemed outlandish. Now, with webcams and Reality TV, it seems much more plausible.
Visual Effects of Awesome: Though in a different way than you'd normally expect. Truman is essentially an effects-less film, but dozens of little touches exist throughout, most notably the subtle altering of a skyline to make it match the Geodome's shape. Everything looks so right that you wouldn't notice it until you were looking for it.
What an Idiot: Meryl, deciding to do a Product Placement while Truman is clearly starting to catch on to the masquerade and is having breakdown as a result. Made worse when she continues to do so even when Truman calls her out on it.
That could be a case of a "Stick to the script or else" directive; later on, when Marlon breaks the fourth wall ("He's gone!"), Christof just about shits a brick and kills the feed.