Have you seen Time Bandits and The Adventures of Baron Munchausen?
Some people think of those two movies forming a trilogy with Brazil that cover the stages of life, going from the excitement and adventure of childhood dreams, to the loss of innocence and disillusionment of being a working adult, to the selective reminiscences of old age, with a tendency to romanticize your own past experiences.
I think of Sam in Brazil as being the everyman who lost his dream, and settled for being a cog in a big machine, without any realization of the monstrous machinations going on around him and indeed implicating him. He doesn't have anything against Buttle or his wife, but he is part of the horrifying bureaucracy that eventually killed Buttle in the name of "protecting" the populace from terrorism.
Sam longs for happiness with the girl of his dreams, but in real life she is not what he thinks she is. He doesn't really fit into the system that everyone else seems able to navigate, partly because he can't let go of his youthful idealism (and dreams of heroism) to climb the ladder like everyone else. Those in power are obsessed with security, surveillance, and regulating and automating everything people do, to the point that Sam is helpless even to keep his apartment at a comfortable temperature. He takes the "easy way" by letting Tuttle do the repairs, and by going outside the system he invites chaos into his life.
In the end, he's unable to cope with harsh realities, the demands of ambition, rampant consumerism and politics he can't grasp. He retreats into madness, losing himself in imagination and in effect creating his own reality to escape the brutality of the "grown up" world.
At least that's what I got out of it. :)