At the risk of appearing a crazy conspiracy theorist, I have been interested in the assassination for quite some time. Other interests - WW2, The Cold War, Communism, Politics and The Mafia- meant JFK was pretty much the sweet spot that coalesced all of those into one single moment/event. I was born in 1974, knew of it as a historical event, I saw the Zapruder film when I was about 12, and never really given it much thought- especially as those that challenged the Warren Report, then and now, were depicted as 'crazies' pretty much.
It was a holiday I went on in 2009 to Cuba that got me looking/thinking about it more. I was reading up about the history of the country, deciding where to visit and stuff like that and ending up reading more about the Bay of Pigs, the Missile Crisis and the embargo. This reading led directly to Kennedy, obviously, and I started reading the crazies books. The main thing I could never understand, what was Oswalds motivation- why would a US Marine defect to the USSR, at the height of the Cold War and claiming to be a Marxist, want to kill a leftish President who was holding off invading an essentially Communist state. On the face of it, Oswald would not have known the efforts JFK and Bobby were secretly making to bump off Castro. Just this, the idea that the US Marines would accommodate someone who was openly communist be in the Marines, leave abruptly, defect, live in the USSR (like other "Defectors" from the US military did around the same time) and then just be allowed, facilitated even, to return. It just didn't make sense.
The sheer amount of questions the whole affair raises, almost at every turn, from the Medical stuff, Oswalds presence and actions in New Orleans/Mexico (if he were there), the mercenary missions that the CIA were funding out of Miami against Cuba, the General Walker shooting, Tippet, Oswalds employment prior to the school book depository, some of the deaths surrounding the assassination (de Mohrenschildt, Rose Cherami), foreknowledge of the plan to assassinate JFK (Joseph Milteer) or the other assassination plots in Miami and Chicago that didn't go ahead in the weeks before Dallas.
It should be remembered, the Warren Report isn't the final word on the assassination from the US Govt. The House Select Committee on Assassinations in 1978, which was set up to investigate JFK and MLK primarily, though the Malcolm X and RFK assassinations also struck me as bad luck, four such events in such a period of time, had this as one of their conclusion:
"The committee believes, on the basis of the evidence available to it, that President John F. Kennedy was probably assassinated as a result of a conspiracy. The committee is unable to identify the other gunman or the extent of the conspiracy".
This sentence in itself wholly discredits the Warren Report and makes another truthful investigation warranted. Especially given the turn in US foreign policy, and politics, from pretty much the second after 12.30pm on the 22nd November 1963. I'm not saying LBJ did it- though he's got a wholly interesting history himself. But it's 'odd' that at least two of the Watergate burglars -Frank Sturgis and E Howard Hunt- have long been associated with killing JFK.
For my money, and I know you've not asked, Oswald was a right-wing loony, probably involved with the John Birch Society, who was selected from the Marines to be a part of Operation Redskin, which was a false defector program that the CIA ran in the late 50s. Upon the end of that assignment, he was undercover/pretending to be involved in far left groups (Fair Play for Cuba Committee) in order to 'out' Commies. I think there was a CIA false flag operation in Dallas, that Oswald was involved in, essentially to shoot at Kennedy but miss. Triggering, if you pardon the pun, a desire by the US population to overthrown Castro/invade Cuba. Unbeknownst to this group, a second group of far-right paramilitaries, disaffected Bay of Pigs veterans, who knew of this plan due to their CIA connections/Cuba Missions stepped into the footsteps of it and shot for real. Oswald was as surprised as Kennedy when he shot and someone else hit. I think this'd explain his actions afterwards. I think that'd also explain why the US Govt have been so reluctant to reveal what actually happened and why there is such confusion around the case. They were pretending to kill him to cause a war but some of their contractors actually did it.
If you're at all interested in the topic, I'd suggest John Simkin's excellent JFK resource Spartacus Educational website. Have a google about these fella's too, beyond those already mentioned, Gerry Hemming, Lawrence Howard, Loren Hall and Rip Robertson. Some real 'crazy' stuff going on in Florida in the early 60s in relation to clandestine attacks on Cuba by Mercenaries.