The interactions between Thor and the other Avengers. Always puts a smile on my face. The next Avengers movie should definitely have a funny scene with this in it. XD I feel like Thor would call him metal man though.
I think he thinks it's funny how NOT original Volstagg is (and that it's darkly funny that things haven't really changed). Because his reaction to Sif vs Volstagg is actually very different. -- I feel bad for Loki.