1. Apple and Microsoft

Frenemies since: 1977, when a tiny software company called Microsoft provided the BASIC programming language for a new computer called the Apple II.

Acts of friendship: Microsoft enthusiastically embraced the Mac when it was released in 1984–Bill Gates raved about it in public and Microsoft apps such as the at-first-Mac-only Excel gave Apple an important boost. And then there’s the legendary Microsoft bailout of Apple in 1997, shortly after Steve Jobs’ return to the company he co-founded. (At the only Macworld Expo keynote ever to provoke boos from the audience, Jobs and Bill Gates explained that Microsoft was investing $150 million in the still-sickly Apple, promising to continue development of Office for the Mac, and supplying Internet Explorer as the Mac’s default Web browser.) Did I mention the famously chummy onstage appearance of Gates and Jobs at the 2007 D conference?

Acts of enmity: Geez, where do we start? Steve Jobs accused Bill Gates of ripping off the Mac even before the Mac shipped; Gates in turn compared Jobs to a guy who stole a TV set (ie, Xerox’s ideas about user interfaces) and was pissed at another thief who arrived on the scene a little too late. In 1988, Apple sued Microsoft for violating its Mac-related copyrights (the two companies eventually settled). In the 1996 PBS documentary Triumph of the Nerds, Jobs said “The only problem with Microsoft is they just have no taste.” Steve Ballmer greeted the debut of the iPhone last year with guffaws of disbelief. The two companies’ current ad campaigns have devolved into snippy, self-referential commentary on each others’ misdeeds. I could go on.

Current state of the frenemyship: Same as it ever was. For more than thirty years now, these two companies have engaged in this weird, tense, ultimately mutually beneficial tango. If it ever ends, the tech world won’t be anywhere near as much fun.

Okay, now it’s your turn: Please tell me about the tech frenemy relationships that don’t appear here, but should have. There are lots of them, I know…

(Image from TIME archive.)