Originally Posted by psylockolussus
Well, Thor/Loki haven't been in good terms, Frigga was killed and Loki seemed to be mourning about it when we saw Thor talked to Loki. Shape-shifting into different people just seems so unnatural for them to do right after Thor asked for Loki's help. I'm sure you wouldn't joking around right away if you were Thor or Loki.
Loki is a trickster god. Kinda his wheelhouse to use that moment to taunt Thor.
It was a funny moment but it was 100% in character for Loki. Using sarcasm and insults and taunts against Thor is absolutely perfect. Remember, Thor had also just told him that he wasn't going to talk about Frigga to him, so what else was he going to do?
Also, have you never read a Thor comic? Loki does this all the time, even when things get emotional for him.
It really was so well executed.