In early season 2012, I was adamant that they should start Matt Flynn over Russell Wilson..
This is mine as well. I was pretty excited for the Matt Flynn trade at the time and thought another Green Bay backup could turn out as well for us as the last one, so I wasn't pleased by the Russell Wilson decision. How wrong I was!
My next closest wrong was in thinking the big contract they gave Shaun Alexander wasn't a bad move. I mean, he was arguably one of the two or three best offensive players in the league at the time so I figured he was worth it. More knowledgeable folks than I at the time talked about how quickly things can go downhill for RBs after they hit a certain age, but Shaun had always done a good job of protecting himself from injury so I thought he would be the exception to the rule.
He was not. (Still belongs in the Ring of Honor, though).
I, however, was not shocked by us losing a 10 point lead at Super Bowl XLIX. That wasn't based on my thoughts as a Seahawks fan and more just based on my knowledge of what Tom Brady was capable of. The injuries on our defense as well made me more than aware it was possible.