There are lots of reasons that Senators like the filibuster (and it's cousin, the hold): bottom line is that in many cases, those rules and norms work well for individual Senators.

Unless, of course, they don't.  Shifting from a Senate in which the minority will use supermajority rules only to obstruct rare very important issues (pre-1970), to a Senate in which the minority will use supermajority rules to obstruct every major item on the majority's agenda (beginning in 1993), to a Senate in which the minority insists that almost every single item, controversial or not, needs 60 votes to pass (the new GOP standard in 2009) has changed the game. 

It's also true that as much as Senators and other political players act on incentives, they also may act -- or at least be stirred into action -- when they get annoyed.  No, really; there are lots of things that are in our self-interest to do, but we don't really notice them, or we don't bother dealing with them, until something happens that gets us annoyed, or offended, or outraged.  And so I think Ezra Klein is exactly correct about Jim Bunning's pointless filibuster against extending COBRA relief and unemployment benefits:]]>