The Marvel Misunderstanding Method was the plot device of choice in the Silver Age to get heroes to battle each other.

The misunderstanding for the issue-long fight in FANTASTIC FOUR #73 was set up in DAREDEVIL #38.

 

It takes place during THOR #150 when Thor was still depowered by Odin which explains why he didn't defeat the Thing with one punch. Continuity can be a wonderful thing in the right hands.