The best was my mother-in-law finding out that her contacts were all lost when her Outlook calendar got corrupted. She didn't even use the Outlook calendar.
And of course, because she didn't have a hotmail account, her contacts were stored locally, so there was no backup.
Installing a mail client, debugging weird IMAP/POP/SMTP issues that come up from time-to-time - not fun.
My mom already knows (for some definition of 'knows') how to use a web browser to view web pages. Using it for email is much easier.
Also, it's easy for me to login into her account and see what happened when she said her mail didn't go through or whatever.