In Thor: The Dark World, what is the significance of the Erik's nude scene? Is it just for comedy effect? But if I remember correctly he justified it, but I don't understand the point. Even he was shown pant-less again in another scene. Is there any justification for it or just a comedy oriented non-justified scene?
Personally, I believe that it was simply to show that he really have lost his mind. But that pants-less scene was done when he seemed completely sane, thus it seemed as if it's because of his natural queerness. Indeed yes, I think it was mentioned that Erik Selvig's mind hasn't completely returned sane after Loki invaded his mind. To quote Selvig himself:
I had a god in my mind.
In addition, Selvig also said something like this:
Finally, The world is crazier than I am.
It shows that he is fully aware that he is crazy, and someone who can asses himself as insane, is, usually, someone who still retain a degree of sanity. This is completely different in behavior than what he did at Stonehenge, suggesting that it was indeed an action that was completely not deliberate. He didn't seem to show any shame or regret in doing that, though, which I guess attributes itself to the partial madness.