IIRC from barakta's information manglement degree, there are two types of people: those who file everything neatly using folders, flags and things, and those who wang everything in a single folder and rummage through it to find things. (There's an orthogonal axis for people's ability to use the software effectively, eg. to automagically categorise incoming mail, or to search for things.)
Proper Email Clients beloved of Old Internet People were designed for the former, and then in the mid-2000s Google came along and used their search engine technology to make email work really well for the latter. As someone who uses folders extensively, I find gmail's approach infuriating. (Also because it hates automatically generated emails, and likes nothing better than to chuck the messages from cron warning you of an impending disk failure in the spam bucket. In the interests of equal opportunities ranting, Thunderbollocks's ongoing failure to IDLE on folders properly is another point of consternation - maybe all *your* new mail arrives in the inbox, but mine frequently arrives elsewhere. Sort it out, devs.)
Of course, when everyone's required to use Outlook for ork purposes, you get the worst of both worlds.
