Remember with the CARES Act, McConnell tried to jam the Dems by presenting a bill without their input and daring them to vote against it in the middle of a crisis (he felt that Pelosi had commandeered the process for an earlier stopgap bill and wasn't happy IIRC). But the Senate Dems voted as a bloc against it, even Manchin. McConnell did the fake outrage about playing politics blah blah then they negotiated a bill. $600 bonus unemployment, PUA, PPP, $1200 checks etc.
Then Lindsey Graham, Tim Scott, and Ben Sasse threatened to blow up the process over the enhanced unemployment. At which point Bernie Sanders told them if they did that, he'd blow up the process over the weak corporate oversight, and they got in line and the bill got passed.
Which is all to say that besides the usual dysfunction and brinksmanship and the ideological gap (Dem opening bid is the $3 trillion HEROES Act, GOP opening bid is corporate immunity for COVID related civil suits), there's probably a ton of butthurt going around on the personal level.