CHICAGO (AP) - Barack Obama appears to be enjoying his last few weeks of pondering the nation's problems without being held accountable for them.

The president-elect teased reporters and New Mexico Gov. Bill Richardson, his choice for commerce secretary, during a brief, lighthearted news conference Wednesday. It stood in sharp contrast to Monday's event, where a solemn Obama was flanked by six grim-faced appointees, including Hillary Rodham Clinton, slated to be secretary of state.

On a trip to Philadelphia Tuesday, Obama briefly greeted school children and later chatted up journalists at the back of his charter plane, an occasional practice he abandoned in the presidential campaign's final months. In all, he seemed to be savoring moments of semi-spontaneous interactions and friendly banter, which almost surely will vanish when he is inaugurated Jan. 20.

Since his Nov. 4 election, Obama has left Chicago only twice, including his Washington trip to meet President Bush and tour the White House. On most days he goes to the gym, works at his downtown Chicago transition office and returns home to his family. Occasionally he dines out or visits friends. A Christmastime vacation to his native Hawaii is planned.

While keeping his travel schedule light, Obama has accomplished many of his transition chores in record time. He has chosen his core White House team and filled half his Cabinet, including the four top posts - at the State, Defense, Treasury and Justice departments.

On Wednesday, he looked like a man with a load off his shoulders.

In introducing Richardson, he indulged in jokes and smiles that were absent from his earlier news conferences. He pretended to doubt his own statement, interjecting, "I've got to check that statistic!" after saying Richardson once set a campaign record by shaking nearly 14,000 hands in eight hours.

He teased one reporter, saying: "I was not going to call on you again," and then uncharacteristically added a personal touch when he invited the first question.

"Let's start with Julianna Goldman from Bloomberg, who was one of the originals, by the way. She was there every step of the way during this campaign," Obama said.

When a reporter asked the clean-shaven Richardson what had become of his beard, Obama insisted on answering.

"I think it was a mistake for him to get rid of it," he said, clearly enjoying ribbing his latest Cabinet choice. "I thought that whole western rugged look was really working for him. For some reason, maybe because it was scratchy when he kissed his wife, he was forced to get rid of it. But we're deeply disappointed with the loss of the beard."

Obama's good mood was a carry-over from Tuesday.

That morning, he emerged from his downtown Philadelphia hotel and bypassed the open door of his heavily secured vehicle. With a broad grin, he crossed the street to a Quaker school where children chanted his name and eagerly shook his hand.

Later, Obama boarded his Chicago-bound plane and ventured back to the press section for the first time since he was elected. Such visits were a fading memory, although in May he had led his staff in a spirited round of the word game "Taboo," defeating the reporters and photographers.

On Tuesday, Obama chomped on a handful of nuts as he greeted reporters with handshakes and hellos, noting a mix of old and new faces.

"Kind of like old times but not really," he said of being on the plane again. "It doesn't have that breathless pace ... just one city a day!"

Obama stopped biting when reporters tried to ask about future Cabinet selections. He pantomimed a zipped lip, and motioned to incoming chief of staff Rahm Emanuel.

"My minder here is getting nervous," he said, returning to his seat up front and drawing a day closer to assuming the presidency.