8. Going To Jotunheim And Picking A Fight With The Frost Giants
This may be the most d*ckish thing Thor does. Like an angry teenager, he decides to have a little rebellion and go against daddy's orders. However, unlike the ordinary teenager, this results in the deaths of maybe a hundred frost giants, nearly killing his best friends and ruining the peace Odin has managed to broker between the Asgardians and the frost giants. Worse still, King Laufey actually gives Thor a chance to walk away from the fight, but Thor decides to start a war because one of the frost giants calls him 'princess'. If you can't deal with a primary-school level taunt, you really are a d*ck. However, the absolute worst part of all of this is the fact that, by starting the fight, Thor creates the opportunity for Loki to realise that he's actually a frost giant and not Odin's son. This is basically the beginning of Loki's daddy issues and the root cause for all the terrible things Loki goes on to do, up to and including invading Earth and destroying half of New York. If only Thor could have kept his cool and stayed at home, none of that would have happened. Nice work, d*ck.