What is the significance of Mayella Ewell's anger toward Atticus during the trial of Tom Robinson in To Kill a Mockingbird?

EXAMPLES OF ANGER AND MADNESS
IN TO KILL A
MOCKINGBIRD

Tom
Robinson.  I don't believe Tom ever showed anger during the story, but it
may have been temporary madness that caused him to try and escape from the prison in
broad daylight.
Mayella Ewell.  Mayella showed
her anger throughout her questioning by Atticus, climaxed by her outburst calling
Atticus and the jury "yellow, stinkin'
cowards."
Jem.  Jem and Scout argued and fought
occasionally, but he became most upset following the jury's guilty verdict in the Tom
Robinson case.
Scout.  Scout learned to control
her tmper as the story grew, but who can forget her fight with Cousin Francis, when she
"split my knuckle to the bone" on his face?
The
Jury.  Little is said about the emotions of the jury, although Atticus
relates that there was one holdout who wanted to vote "not guilty" before giving
in.
The Prison Guards.  Their only reference was
to Tom's escape attempt (which they may or may not have been angry about), riddling him
with seventeen bullet holes.
Mr.
Walter Cunningham.  Cunningham's moment of madness came
when he led his Ol' Sarum friends to the jail with the intent of making Tom the host of
their lynching party.
The Missionary Circle. 
Miss Maudie remained calm but angry when she sniped at Mrs. Merriweather about her
comments concerning her maid, Sophy.