I don't think that Loki's reasons for trying to take over the Earth are very rational or mature. But Loki didn't come across as rational and mature, just trying to hurt his brother.

But I do think in Avengers he's just random guy with irrational feels towards his brother, no matter how much they tried to talk it out.

In Thor, there's at least context for the crazy things he does.

I'm still a shade perplexed by them being the Thor and the Loki. Are they that on other planets as well?

Oh, and if the staff was working on him, it wasn't in the same way it worked on Hawkeye or Selvig, because there were physical indications of that. It would have to be in the same way it worked on the rest of the Avengers, and I don't think that's pointed to by the text.

What he's doing in The Avengers is a carry over from what happened in Thor. That's the way I read what was happening. The Avengers is him trying to get revenge for what Thor did to him in Thor.

I don't think the staff was working on Loki.

I think it was a conduit to communication but not controlling him.

The way I saw it, Loki cut a deal with the Chaturi leader, but the leader is stronger than Loki so he keeps threatening Loki. And this also fuels Loki's rage.

In my head the leader of the Chaturi was using Loki as a way to get to Earth, and then when Loki was no longer useful the leader was going to kill/imprison Loki.

What he's doing in The Avengers is a carry over from what happened in Thor

Yes, but Avengers should ideally stand on its own, and my point is that this is pretty much the only place it fails. Iron Man and Cap are explained and demonstrated really well, but Loki is underpainted.

I didn't see Loki say he wanted to enslave humanity. Not in words like that, anyway.

I'm getting that from the "free them from freedom" line.

I've got Thor and Captain America to watch today and then I'lll see Avengers again tomorrow, so maybe I will understand your objections better then. And the rest of the discussion.

He also used the word "humanity" way too freely for an alien. I'm not clear on whether he's espousing a Homo Sapiens need to be a certain way, or it's an everyone thing.

Also when Loki first appears and he's talking at Fury, Fury says something like "it doesn't sound like freedom, it sounds like the other thing." I took "the other thing" to mean slavery.

It's kind of hard for me to separate how much I'm influenced by the back stories from the other movies.

While I know that The Avengers should be understandable to someone who had never seen any of the others, but I don't see it as a standalone movie, but as another in a series. And like any series storylines and motivations carry over from the earlier books/movies.

Apparently in interview Joss has said that Loki became insane while falling through the void which is totally stupid just because there's no pointing to that specifically in the movie. So I hope it's not considered canon.

And apparently he also said that Coulson isn't dead. So there's that.