The war between Microsoft and Apple (or let me rather say Bill Gates and Steve Jobs) started in the 1980s, all the geeks know the story but let me repeat... Microsoft was doing DOS for IBM and Apple there Apple II etc machines (before the Mac) so it was Apple vs IBM, Apple then released the Mac - first operating system that got a graphics user interface (GUI) - they stole this idea from the Smalltalk system... Microsoft then wrote software (spreadsheets etc) for the Mac, later on Microsoft released Windows and that stole the market. So yeah, Steve jobs wasn't happy with Microsoft (Bill Gates) for steeling there GUI OS idea even if they stole it from the Smalltalk system... actually if you look at this story both of them are wrong.
Over years there was no love between them... Currently for example you need a Mac to write software for the iPhone/iPod Touch/iPad (known forth as the i-Devices) can't do it on a MS Windows machine.
Personally I see this as wrong... We are customers, we don't care about fights, bad feelings etc that companies got against each other... This if for example why Steve Jobs is wrong - his feelings is always in the way of his business judgement... customers are asking for Flash support on the i-Devices but no his got a thing against Adobe.
Give us what we ask for! Give us what we want! If you give us what we ask for / want without all this other crap (that is the only way of expressing it) then your product will grow and you will become more successful then the company X that you got a thing against.