Clear as day you have a guy here that burns red hot and in a hurry. His whole career dating back to when he was 9 in pee wee sports, Sherman has been a shit talker that has used the smallest bit of a slight to fuel him.
Pretty obvious what set him off here.. for one, he hates Crabtree. Richard Sherman is a shit talker but he also went months without saying a peep about someone.. he's not just identifying a player on each team and saying "you suck, you suck, you're sorry, you're mediocre" etc... but this obviously goes way back and why I believe to an extent that this all started at Fitzgerald's charity event.. but again, in context, maybe wasn't as bad as Sherman made it out to be because again.. Richard Sherman is that type of player where it will not take much for him to swirl it around in his head that he's being slighted.
With that said.. you had that "fight", "argument" whatever.. then you have Crabtree backhand complimenting the Seahawks defense besides Sherman.. and then you have Sherman trying to tell him good game in the heat of the moment and again he felt slighted and that just set him into crazy mode.
I do agree with Warner that this was pre-determined in his head the moment that game ended. Sherman had been dying to have this moment for months. He's definitely not a thug, he's incredibly smart and articulate.. but this was all planned out. If you watch the mic'd up shit about the NFC Championship, he's even telling Earl Thomas that they're about to throw at him. He knew he'd have his chance to make the play to allow him the ability to one, talk down Michael Crabtree and two.. make a name for himself.
Where I do agree with Sherman though is that I don't think he ever thought in his mind that it would blow up to be THIS big to where he's getting CNN interviews and the like either.
Long story short.. I can see where people would be turned off by that behavior and I can see why others love it. It's the same reason why TO is loved and hated.. it's the same reason why Floyd Mayweather is loved and hated.. and on and on down the line with any overly cocky athlete.