1. Government authority figures, especially the police, are arbitrary to the point of insanity:
CENTURION: Now, write it out a hundred times.
BRIAN: Yes, sir. Thank you, sir. Hail Caesar, sir.
CENTURION: Hail Caesar. If it's not done by sunrise, I'll cut your balls off.
2. Those who are blinded by ideology or partisanship are capable of continuing to believe whatever they want to believe, no matter how much evidence piles up to the contrary:
REG: All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us?
3. The masses are sheep:
BRIAN: Look. You've got it all wrong. You don't need to follow me. You don't need to follow anybody! You've got to think for yourselves. You're all individuals!
FOLLOWERS: Yes, we're all individuals!
3a. with occasional exceptions.
BRIAN: You're all different!
FOLLOWERS: Yes, we are all different!
DENNIS: I'm not.
4. And, of course, political parties, especially the more extreme sort, are prone to factionalism:
FRANCIS: Whatever happened to the Popular Front, Reg?
REG: He's over there.
Oh -- and, it's as funny as any movie ever made. Life of Brian is a great, great, movie. I'm not really a major fan of the opening credits & song, and the brief animated interlude with the spaceship doesn't do much for me at all, but otherwise it's outstanding. I've gone back and forth between Brian and Grail over the years...I guess what I'd say right now (and certainly reserving the right to change my mind) is that Grail is a great cult movie, a great nerd movie, with all sorts of bits that true Grail lovers get out of repeat viewings. But Life of Brian is just an excellent movie, one that I'd recommend to anyone -- and anyone not willing to give it a chance is really missing out on good stuff.
I have no idea why Christians would have any objection to any of it; to my (admittedly non-Christian) ears, it's extraordinarily respectful to Christianity, and I would think that the various riffs on the Christian Bible would be a lot of fun -- I know I enjoy them a lot. I guess some of my fellow Red Sea Pedestrians complained about it too, but again I'm not sure exactly why.
Anyway, if for some reason you haven't seen it, do something about it right away (and it's on IFC this week, probably multiple times; I know I set my DVR). Life of Brian, highest recommendation.
(Update: A couple of days after I ran this, I realized that I missed one. Fringe political groups are prone to futile, self defeating actions, as seen by the Judean People's Front Crack Suicide Squad.
And I guess that means I need to renumber: Amongst the iconic political moments in this movie are such diverse elements as...).