WASHINGTON, June 6 -- The breakup between the president of the United States and the world's richest man is unfurling much like their relationship started - rapidly, intensely and very publicly. President Donald Trump on Thursday lamented his soured relationship with Elon Musk, his adviser-turned-social media antagonist. Trump said he was "very disappointed" with Musk after the billionaire former backer lambasted the president's signature bill of tax cuts and spending plans. Trump suggested Musk, who left the government last month after spearheading the tumultuous Department of Government Efficiency, misses being in the White House and has "Trump derangement syndrome."He added, "I'm very disappointed in Elon. I've helped Elon a lot."P17...