I can't believe people went crazy over this line. lol.  They had to get a linguist to solve this?  LOL.  Sheesh.  Anyway, it's exactly what I expected he said.  Not that Weyland didn't tell us exactly why he was there... Twice.  It should be as easy as solving for x in x 2=4.

Adds fuel to the idea thagt the Engineers found our attempts to conquer death an unacceptable violation of the rules of life. Every king has his reign then he must die. The Engineer at the beginning gave his life so that humanity might be created. Perhaps we never did anything wrong, we'd just come to the end of our cycle. That planet wasn't a weapons factory, it was simply the cleaning crew.

Yeah I'd say his reasons for freaking out were as simple as: "I woke up surrounded by strange little beings in weird suits asking me to grant more life, they were on my ship and I felt threatened!!!  I'm sure the  last few minutes before he went in the cryo sleep container were pretty hectic and stressful, so his actions were pretty understandable and justified. 

I felt like this movie did a lot of explaining without words and though I agree there were some questions left unanswered, it's not as cryptic or confusing as more and more articles and reviews would have you believe.  I'm sure repeat viewings with a slightly more focused attention span will help more people get it.  The excitement of having a new Ridley Scott film in the Alien universe has created the need to overthink, as exactly intended I'm sure!!

Brilliant film, it will be remembered with great regard.

Yeah, SmokingFrog77 hit it right on the head! The reason the Engineer hulked out was because the Engineers believe that self-sacrfice and knowing when your time's up as a leader is the most noble of virtues. Weylan showing basically begging to live longer was pitiful and self-serving, all the nasty petty emotions the Engineers despise. That particular Engineer probably went into stasis already disgusted with humanity and thinking that their sacrfice in creating our race had been a big failure. And then here comes the very same humans right up to his very door pretty much confirming how petty and vain they are.

Seriously, it's no wonder the Engineer went beserk. We're just a sore reminder of the mistake they made in creating us. They're probably not used to their mistakes coming back to flaunt themselves in the flesh.

Honestly, the script was left intentionally vague so that people could fill in whatever meaning they wanted to attribute to certain actions. Much like Lindleof's bad writing on 'Lost'. There was contradictory action by the characters in the script (ie. the biologist who is scared of a 2000 year old dead body (which he should have been examining in the first place) so much so that he runs away from it, yet he sticks out his hand to make friends with the penis cobra in the very same chamber!). 

I half expected the smoke monster to show up part way through the movie, only to disappear again because of some out of body experience, or some other pseudo-science fiction plot device or vague explanation (maybe 'Space Jesus' wished him away!). 

You know a movie is bad when your two best actors (Theron and Pearce) are only there as characters to explain why the plot device of the lifeboat and the medical bed are aboard the Prometheus in the first place. 

LOL,  I only posted this like 5 days ago

IMO the engineer looked at the group and was annoyed by these insignificant beings not only being in his ship but the nerve to try to communicate with him, these gnats, their creations, how dare they.

 As I keep saying, the fans' theories and fillers and chat - are far more interesting than what was in the movie ... hope the sequel is better ... but ain't holding my breath

With as many "secrets" and "spoilers" as there have been for this I'm still suprised by how little we can nail down, I honestly think the movie would have been beter if scott did it on his own and left the Lost effect stranded on an island. That being said I still enjoyed the movie, actually liked the 3d and will be happily waiting for a sequal and any behind the scenes or deleted footage when it comes to stores.

I tend to agree with the engineers basic disgust as the reason for him getting angry, not only at Weyland's holding onto life but of the artificial creation of David in front of him. I mean even the engineers ships suits, controll pannels always look more grown than made, perhaps it is all organic tech, and seeing a man walking with aid of machines as well as a machine imitating life caused his "hulk out"

 david told the engineer "the avengers own".  the engineer got mad cause he is a tdkr fan. that's all this is.

@Ryodin perfectly put, I agree.

Ridley said that they wanted to show that Jesus was an emissary of the engineers and that his crucifixion was basically the last straw. Humans and their greed and wars and religions had gone wrong. I think like you said the virtue of sacrifice like the first engineer did to seed the earth, all of that has been lost to humanity