For the past few years I've seen almost no bipartisanship in Congress. They're in deadlock. I don't know where this total disregard for bipartisanship came from but without it, congress can't do anything and thus they are the worst congress in history. Personally I blame the far right, or the tea party, as their every stance thus far has been, "Our way or no way."
I believe this is one of the worst Congresses in history because they are more concerned with partisanship than getting the job done. If it weren't for the Tea Party members, I believe there would be far more compromise, but due to the extremism, there will be nothing except gridlock. The problem with the "far" wing of any party is their inability to see past their own politics towards the good of the American people. Until we quit being so unbending, we will only have trouble in this country.
One has to only look at one instance. For two years in a row people on long term unemployment have been taken to the brink in the very same fashion. Congress delayed until the last minute in deciding whether to continue paying. From what I read today, they have delayed too long this time around because they were mistaken about which day the unemployment benefits lapse. They thought they had until Sunday to deal with it, but the benefits actually lapse the day before (which is tomorrow). So whoops, a lot of people suddenly have no income. It is not a good way to run a country and extract any respect from the people you govern and it is no wonder they are being called the worst in US history.
The problem with this Congress is that rather than vote for what is best for society, they are so caught up by making sure the other guy doesn't get what they want, that they vote just to cancel out the other party's vote. That's why this Congress has done absolutely nothing.
The current Congress has gotten a lot of bad press for failing to achieve compromise over the fiscal cliff issue, and I do think a lot of that is warranted, but I don't think it makes our Congress the "worst" in US history, especially given that we have Congresses that voted against interracial marriage and civil rights in the past.