A true gem. I think Peter Weir’s The Truman Show is part of informal trilogy (with The Eternal Sunshine of the Spotless Mind and Man On the Moon) in which Jim Carrey found a way to channel his manic energy and rubber-face-pulling into dramatic roles, in films that were not only populist, but also critically acclaimed.
That said, there are a few scenes in which it’s clear Weir wasn’t able to rein in Carrey’s more outré compulsions. Many interesting supporting characters (Noah Emmerich as Truman’s lifelong ersatz pal, who nevertheless seems to have some genuine affection for him, and Laura Linney as a decidedly more professional actor just doing a job) simply disappear from the film. It may not be perfect, but it builds to a very moving emotional wallop at the end.