From a well-placed Hill guy:

Off the record, I think what many GOPers up here are upset about is the chasm between the rhetoric and the actions of those Republican Senators who voted for “pay/go” rules. Just a few weeks ago, the same Senators who said that we needed to “pay for tax cuts” voted to waive those same budget rules for spending in order to increase spending on unemployment benefits. Do as they say not as they do I suppose.