I agree with your comment on Outlook (I use this on a daily basis, go figure) however there's more than that. Its not merely Outlook; its the interoperability between all the Office components which is the big issue IMO. That stuff (VBA) is so extensive that it can be mind boggling (IMO).
I do tech support on a Windows server for a small company. Within certain business hours people can ring me with questions, e-mail is obviously no problem, I do regular maintenance on the server and to top it off the director of said company gets a weekly report from me where I tell him how many phonecalls were received, how many e-mail inquiries were received and a summary on the maintenance on said server. This doesn't effect costs, but the director likes to be kept in the loop (its a small company, but bigger than mine is).
You don't really think I'm typing all of this ? ;-)
I click my Word template, which then checks the current date, contacts Outlook and starts checking the (dedicated) inbox for that company to see how many e-mails there are between that day and seven days back. Phonecalls are monitored by me through Business Contact Manager (free yet invaluable Outlook 2010 extension) and the same applies.
So all that's left to do for me is fill in what I've been doing on the server.
THAT is IMO one of the key assets of MS Office. With a few lines of VBA code you can make it do whatever you want, and it can save you hours and hours of work.