In the early days of Apple and Microsoft, Steve Jobs and Bill Gates got along — Microsoft made software for the Apple II computer, and Gates was a frequent guest in Cupertino, where Apple is headquartered.
But the tides started to turn in the early '80s, when Jobs flew up to Microsoft's headquarters in Washington to try to convince Gates to make software for the Macintosh computer. Gates later described it as "a weird seduction visit" and said he felt like Jobs was saying "I don't need you, but I might let you be involved."
Still, they remained relatively friendly until 1985, when Microsoft launched the first version of Windows and Jobs accused him of ripping off the Macintosh.
"They just ripped us off completely, because Gates has no shame," Jobs later told his biographer, Walter Isaacson, to which Gates replied: "If he believes that, he really has entered into one of his own reality distortion fields."
The duo traded barbs for years, with Jobs calling Gates boring and Gates calling Jobs "weirdly flawed as a human being." Tensions remained high even after Microsoft invested in Apple to keep it afloat, with both Gates and Jobs insulting each other and their companies' products time and time again.
Still, they clearly respected and admired each other, despite their animosity. When Jobs died in 2011, Gates said: "I respect Steve, we got to work together. We spurred each other on, even as competitors. None of [what he said] bothers me at all."