First of all, the release has been bowdlerized, with redactions of e-mails that were previously regarded as “routine” suddenly upgraded to “classified,” so as to shield their contents from public scrutiny.  The New York Times:

The State Department said late Tuesday that portions of two dozen emails from this tranche had been redacted because they were upgraded to “classified status." The emails were sent in 2009, and their contents were apparently not sensitive enough to national security at the time to have required a higher classification status. The State Department described the move “routine” when the government discloses documents to the public.

Second, Hillary was out of the loop, and she knew it.  From the NYT:

“I heard on the radio that there is a Cabinet mtg this am,” she wrote aides on June 8, 2009. “Is there? Can I go? If not, who are we sending?” (It turned out it was not a cabinet meeting but one for lower-level officials.)

Four days later, she emailed aides after showing up for a 10:45 a.m. meeting at the White House only to be told it was canceled. “This is the second time this has happened,” she wrote. “What’s up???”

Third, she reciprocated, by making herself inaccessible to White House aides, by keeping her personal e-mail (on her private server) secret from them, until they had to ask for it.  The NYT:

Before Mr. Axelrod sent her the message, he had to ask her aides for her address, and the aides checked with her first about whether it was O.K. to give to him. They similarly asked whether it was all right to give her address to Rahm Emanuel, then the White House chief of staff.

Fourth, she was jealous of Henry Kissinger for his access to the White House and had a low regard for her boss, President Obama.  She feared looking bad by sharing a stage with Kissinger.  The Los Angeles Times reports:

In one December exchange with a top aide, Philippe Reines, she expresses concern about sitting for a joint interview with Henry Kissinger, which might raise unflattering comparisons about the two secretaries’ access to their presidents.

 “I see POTUS at least once a week while K saw Nixon everyday,” she notes, calling it a potential issue. “Of course, if I were dealing w that POTUS I'd probably camp in his office to prevent him from doing something problematic. Do you see this as a problem?”

Finally and most importantly, as covered here, the president of the United States was kept in the dark about diplomatic activities of his secretary of state through the use of a secret, off-the-books aide, Sidney Blumenthal.  This is not how our government was designed to operate.