President Obama, in his final news conference of the year, sought to put the best face on a difficult first year of his second term.
Speaking a few hours before he heads to Hawaii for a two-week vacation, Obama is meeting with reporters at the White House.
He touted the improving economy, saying 2 million jobs had been added in 2013, with the unemployment rate now at its lowest level in five years.
"2014 can be a breakthrough year," he said.
Obama said that despite the difficulties with HealthCare.gov, "more than a million people have enrolled for new health care coverage since Oct. 1."
Asked later what his biggest mistake of the year was, he said: "When it came to the health care rollout, even though I was meeting every other week or every three weeks emphasizing that consumers have a good experience ... the fact is that it didn't happen in the first month, six weeks, as it should have, was not good.
"I'm in charge, we screwed it up," he said.
He said despite the technical problems with the website and "about as bad a bunch of publicity that you can imagine," many people have still signed up, proving "the demand is there and the product is good."
Obama praised Congress for passing a budget, but said it's "too early to declare an outbreak of bipartisanship."
He found a moment for a joke, saying his New Years resolution was "to be nicer to the White House press corps."
Update at 3:15 p.m. ET. We Should Test If Diplomacy Will Work With Iran:
"It's important for us to test whether that's possible," he said, adding that the alternative "involves the possibility of some sort of a conflict."
"I sure would rather do it diplomatically," he said. "We lose nothing during this negotiation period."
Update at 3:09 p.m. ET. On His Nomination Of Sen. Max Baucus As Ambassador to China:
NPR's White House correspondent Ari Shapiro asked whether the exit of Sen. Baucus - considered a key Democratic figure for possible tax overhaul - would damage the chances of that happening.
The president said if Congress wants to overhaul the tax code, the White House is "willing and eager."
Update at 3:05 p.m. ET. More on Affordable Care Act:
"It's important that as we transition to higher standards and better insurance, that we also address folks who get caught in the unintended consequences of those changes."
Update at 3:00 p.m. ET. Edward Snowden Leaks Did 'Unnecessary Damage':
"I have said before that this is an important conversation that we needed to have," the president said about the reevaluation of domestic intelligence activities. "I've also said that the way these revelations came about was damaging."
"For all our warts, ours is a country that abides by the rule of law, that cares about privacy, that cares about our constitution," he said.
Update at 2:55 p.m. ET. Health Care: 'We Screwed It Up.'
Asked his biggest mistake this year, the president said the health care rollout didn't work in the first month to six weeks.
"Since I'm in charge, we screwed it up," he said.
Update at 2:50 p.m. ET. Thanks NSA Review Panel:
The president thanked the panel he appointed to review NSA spying activities, saying panel members "did an excellent job."
"What we're doing now is evaluating all the recommendations that have been made," he said.
"There have not actually been any instances where the NSA acted inappropriately with relation to this data," he said, adding that the U.S. intelligence community needs to figure out if "we accomplish the same goals in ways that give the public more confidence."
Update at 2:40 p.m. ET. HealthCare.Gov, Lack Of Immigration 'Frustrating.'
On his inability to get immigration reform passed, the president said: "The fact that it didn't hit the timeline that I'd prefer is frustrating, but it's not something I brood about."
He said the Healthcare.gov problems were also frustrating.
The latest approval polls show the president at his lowest-ever level.
"My polls have gone up and down a lot in the course of my career," he said. "If I care about polls, I wouldn't have run for president."