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.
Often overlooked but still awesome is "Brian", the credits song, which grants a massive booming orchestra and an incredibly talented singer to some of the silliest Coming of Age lyrics you've ever heard. "And he started to shave / And have one off the wrist / And want to meet girls / And go out and get pissed..."
After the success of Spamalot, Eric Idle wrote a comic oratorio based on Life of Brian called "(Not the) Messiah," which had dozens of new songs, a full orchestra, and is written in the style of Handel's Messiah. It may in fact be the only comic oratorio in existence.
Big Lipped Alligator Moment: For a Monty Python film, Life of Brian is very reasonably paced and well-grounded — save for the scene where Brian falls off of a tower to be saved by a passing flying saucer, taken into space to pass through an intergalactic war, and then brought back to Earth in a crash of alien metal — right at the foot of the same tower. The scene was added merely to give Brian a way to escape the tower.
Some have speculated that it may be a reference to the conspiracy theories regarding UFOs popping up in the backgrounds of paintings of Christ. Given the amazing amount of research done it's plausible, but doesn't seem to be the case.
I thought this was a reference to some of the weirder stuff the Mormons believe in.
A few ministers said that Brian was supposed to be Jesus. They had come into the theater late and missed the first fifteen minutes, which establish that Jesus exists in this universe as a separate person from Brian.
Even if Brian was Jesus, the charge that they were mocking him doesn't really stick — Brian is the Only Sane Man.
Well, presumably if they thought he was Jesus, bits such as when he appears nude after having sex with Judith don't go over that well.
Dude, Not Funny!: Far too many examples to list, depending on the viewer's taste.
Ear Worm: Always look on the bright side of life...
Funny Moment: What's so funny about "Biggus Dickus?" I have a vewy gweat fwiend in Wome called "Biggus Dickus."
Tear Jerker: The bits between the botched (or successful, depending on your outlook) Suicide Squad raid and the finale. Brian is being crucified, and not even those he loves are going to help him. His lover takes his "martyrdom" with pride, and his mother berates him and leaves him for dead.
Subverted, however, when "Always Look on the Bright Side of Life" starts up, which is such a happily optimistic song that it somehow manages to make the crucifixion of the main character and a whole load of other people really cheery.
The Woobie: Brian, he never gets a break long enough, and every one of his friends leave for death.