Email servers are crappy too.
My father's ISP email service only recently added support for IMAP and it doesn't support syncing the inbox for just the last 3 days. You have to sync the entire inbox. Thankfully, the WinMo client has a certain limit, and it errors/timeouts before it manages to fetch some 10GBs of email. Cue him spending his 20MB allowance for 1mbps in less than a week, then downloading emails at 64kbps.