(S05E10) I'm really starting to think that Carter Bays was telling the absolute truth when he told Mike Ausiello that the writers threw the Barney-Robin relationship into the trash heap. He wasn't being coy about a future plotline; I get the feeling that the writers wanted Single Barney over Relationship Barney and wanted to make sure they got there as quickly as possible.

Why else would we see an entire episode of Barn trying to get laid while wearing Marshall's old overalls? Here's the problem, as others have mentioned: we've seen how much of a good guy Barney can be. So seeing him back to his old tricks seems a bit emptier than it used to, doesn't it?