it's an ego thing. there's this prick I work with who'll never admit he's wrong, even when he knows nothing about the subjet. Example: he's into linux, but hasn't used a mac since OS9 or older. I've got like, 3 linux machines, so I can put forth an argument to show that macs are significantly easier to use for joe average, etc, but he just dismisses them all as 'crap'. Really makes my blood boil. If he doesn't know something, he'll just say it's 'easy' and mumble some words to do with the general subject, then swiftly shut up. He slates .net, despite knowing nothing about it. His only skill is php, so you'll find him doing high level business application development in a web browser with php instead.
asshole.