In the new Outlook I find that the button 'Ignore conversation' is extremely helpful. 
This thread actually makes me feel better about our users. At least they all know how to use the mouse and there have been very few cases or 'reply all' (nothing too embarrassing or mean so far).
Although our engineers really like adding their personal touches to the paper notes that HR posts sometimes in the common areas. E.g. one note got updated from "ALL, ..." to "Y'ALL,..." (we speak Southern English here ).