I agree with these observations by Patrick Smith, writing at Salon:

[T]here is an awful lot of yammering going on. There can be up to a half-dozen cabin P.A.s before your plane even reaches the runway, sometimes in multiple languages. Is this really necessary? To some of these announcements we grant a pass. Surely there's nothing out of line about a brief welcome-aboard speech, for example, or other practical reminders. However, if there is one hideous and glaring example of excess, it has to be the pre-departure safety briefing. Is there anything more tedious? . . . With a pair of shears and some common sense, the average briefing could be trimmed to half its length, resulting in a lucid oration that people might actually listen to.