I'm kinda neutral on JFK.
He stood up to the USSR/Cuba, made us The technology leader with the moon landing goal and gave a modest tax cut.
OTOH, he botched the Bay of Pigs badly, significantly escalated Vietnam, made the Cold War "colder", and with his infidelity he marked the beginning of a long string of truly horrible presidents that resulted in a lack of respect for the office of the President and government in general.
JFK can be aptly described as our nation's first adolescent president -- a term (for better or worse) that lay dormant for a while but resurfaced in the Clinton and George W. Bush administrations.