Just a quick comment after being "warned" by Excel about something for the umpteenth time, it would be great to have non-critical dialog boxes be optional.
For implementation, when the warning comes up the first time, have a checkbox to indicate that it should/should not be shown the next time. To turn a dialog box back on, the options would have a list of possible dialog box messages, with a help link to show what the popup looks like.
I realize there could be an issue where a person remembers where a popup was, but not what it said, and that searching through a large list for the message would be difficult. Just wanted to relate the idea