The Briefing is an important part of any critical mission that is assigned by superiors. James Bond films include a briefing scene where Bond is given his mission by M. Military ops are bound to have a briefing. There were even briefing scenes in CHiPs, where Jon and Ponch were given the lowdown on what particular criminal of the week to look out for.
So naturally you should make use of the briefing scene whenever you have the opportunity to give a mission to a group of PCs. It's not only a great opportunity to leverage a well-known fiction trope in a game scenario, it also gives you the chance to lord a powerful NPC who they're not supposed to kill over the PCs.
And if they decide not to accept the mission... perhaps something will self-destruct in five seconds. In their faces!
General Dodonna: As per our surveillance performance metrics we've achieved total positional understanding of our competitor's targeted aggression platform.
Chewbacca: We've located the Peace Moon.
General Dodonna: Critical path analysis indicates its location profile is counterbalanced by a mission-critical occlusion, namely the local major mass resource.
Chewbacca: It's on the other side of the planet Yavin.
General Dodonna: Going forward, we are leveraging our positional certainty into a temporal proximity advantage.
Chewbacca: And it's coming this way.
Luke: Holy crap! It's going to destroy us all!
General Dodonna: Your concern is noted, but fear not: a catastrophic failure paradigm is indeed integrated into our best-fit modelling.
Leia: We're not paying you by the word, are we?