I was going to say that maybe Tom's face reflects the duality of his personality. I still think there's a bit of Tom in Loki. I mean he seems like a good guy most of the time, but we all have a darker, more hostile side to our personalities.
I have to say...this interview for the first Thor makes it rather hard to watch Tom as the interviewer is a bit on the flaky side.
This would be my greatest fear going to a convention, to meet someone trying to cosplay as their favorite character and failing miserably at it.