John At His Most Despicable

In my view, Lennon's wort behavior was not any specific act of violence,
his departure from the Beatles, his demonizing of McCartney or his
abandonment of friends like Nilsson, Jagger and Moon upon returning to
Yoo in the mid-70s.
Rather, it's the way in which Lennon ended his family with Cynthia and
Julian that I find most unconscionable.  Cynthia returned to Kenwood
from a trip to Greece, where she had been joined by Jenny Boyd and Alex
Mardas.  However, the place was "eerily silent."  The door was unlocked.
 "John?  Julian?  Dot?  Anybody home?" she called.  Finally, she found
John sitting with Yoko on a small couch.  Yoko fixed Cynthia with a
"confident" stare.  After several minutes, Lennon addressed his wife: "Oh, hi."
Cynthia was so disturbed by Lennon's and Yoko's demeanors that she "had
to get out immediately."  She returned to Jenny and Alex - who plied her
with wine. By some accounts, Alex proceeded to take advantage of the
thoroughly inebriated Mrs. Lennon.
A few days later, Alex told Cynthia that Lennon was suing her for
divorce, on grounds of adultery -- and that Alex had agreed to testify
on Lennon's behalf.
The trauma of all of this must have been overwhelming.
Yet it is also the culmination of Lennon's LSD-crazed behavior, after he
had made a fool of himself with Brigitte Bardot (assuming the lotus
position and telling her to "feel the vibes") and attempting to hold a
press conference to announce to the world that he was Jesus Christ (his
bandmates had persuaded him to wait a few days before going public with
the news).  It was on that sane day that Lennon summoned Yoko to
Kenwood, recorded Two Virgins, and consummated his relationship with
her.
If Lennon had not fried his mind on acid, the John-and-Yoko freakshow
would not have happened.