Washington (CNN) -- The end of 2012 was set to be Secretary of State Hillary Clinton's farewell tour as the top U.S. diplomat. But things clearly changed.
After logging more than 950,000 miles and visiting 112 countries over four years, she is known for keeping a grueling schedule.
President Barack Obama called her extraordinary at a recent diplomatic reception.
"Over the last four years, Hillary has been everywhere -- both in terms of her travels, which have seen her represent America in more countries than any previous secretary of state, and through her tireless work to restore our global leadership, " Obama said.
Clinton enjoys something rarely seen anymore in politics -- a soaring approval rating. It was close to 70% in early December.
"It's because she works hard, does a good job and she cares," CNN political contributor and Clinton insider Paul Begala said. "She authentically cares and she has devoted her whole life to this set of issues to help folks."
It seemed certain that Clinton would end her tenure on a high note. But her closing chapter at the State Department turned into anything but a fond farewell.
Illness, a concussion and a blood clot sidelined her for more than three weeks.
State Department spokeswoman Victoria Nuland said Clinton has received a "tsunami" of goodwill and get well messages.
"She is talking to staff, she is taking paper at home, she sounds terrific, she's looking forward to coming back to work next week," Nuland said on Thursday.
Doctors expect a full recovery.
Clinton still faces tough questions about the September 11 attack on the U.S. diplomatic post in Benghazi, Libya, that killed Ambassador Christopher Stevens and three other Americans.
Clinton tried to calm the resulting political firestorm in an October interview with CNN.
"I take responsibility," Clinton told CNN while on a visit to Peru. "I'm in charge of the State Department's 60,000-plus people all over the world, 275 posts. The president and the vice president wouldn't be knowledgeable about specific decisions that are made by security professionals."
But beyond leaving a mark on her legacy, the Benghazi attack and continuing violence in the Middle East, particularly in Syria, now become unfinished business that Clinton may leave behind.
"[Her term as secretary] can't be ending on a high," said Aaron David Miller, vice president at the Woodrow Wilson International Center for Scholars. "But I think it's part of a broader piece.
"This isn't a slam dunk world. It's certainly a very cruel and unforgiving world abroad. There were no spectacular successes to be had. There were only, as I've described elsewhere, migraines or root canals."
As she moves into the next chapter of her life and a possible 2016 presidential bid, the real question is whether unfinished business might become political baggage?
"She's the most recognized human being, probably on planet Earth. Certainly the most recognized woman on planet Earth. And her relentless travel has helped, to a large degree, to improve American credibility and an image that had reached new lows in the previous administration," Miller said.
"Her challenge is not going to be that Americans are going to be looking back and saying 'how come you didn't fix Syria? Or ... how come the mullahs didn't give up their quest for a weapon?" Miller added.
"I think her greatest challenge is that she's running against history. ... Can you have another four (to) eight years of Democratic rule after the last eight?"