Will it never end? This harping of mine on the subjunctive. Not likely, as I do enjoy foisting it on people.
My previous posts on this fun subject can be found by searching for it in the sidebar right.
Now. Today we shall concentrate on just one specific use of this form. I'll call it the injunctive use. This is when you want to order someone to do something. Or at least strongly suggest that he should (the latter is more realistic with Italians).
The imperative, which is what you use to boss people around, actually takes the form of the subjunctive in Italian, except in the second person ("you" singular and plural), where it has its own form. But note that when you are bossing someone in a formal context you will use the third person i.e. a subjunctive form. Examples: se ne vada (get out), stia zitto (be quiet), si fermi (stop). A famous example of the third person use is the title of the aria from the opera Turandot, "Nessun dorma." This is an order: the speaker doesn't want anyone to sleep. It is sometimes translated as "no one is sleeping" by people who have not studied their subjunctive.
Italian newspapers like to use this in headlines to report on notable people telling others what they should do, which is almost always in vain. The Pope will often be quoted as saying things like "Cessi la violenza/l'odio/l'ingiustizia/la guerra in...!" Violence/hatred/injustice/the war in ... should/must/sure better stop. Politicians of opposing factions tell each other off using the form "A la smetta di fare B," A must stop doing B. Whereupon A does not stop doing B, but tells his opponent C: "C la smetta di fare D."
(Above, famous painting by Raphael showing two Italian kids listening to a lesson about the subjunctive)