@jwz unlike Google, XScreenSaver will not prompt you to call your deceased dad on Father's Day.
https://technologizer.com/2011/06/20/googles-unpleasant-heavy-handed-father-day-surprise/index.html
https://techcrunch.com/2011/06/20/reminder-call-dad-another-notch-in-googles-belt-of-social-fail/