In the case of the Samuel L. Jackson ad, don't worry: it's safe for work. That's unlike the audiobook version of "Go the F*ck the Sleep" that Jackson did the voiceover for. At the end of the ad, Jackson tells Siri to take the night off, to which Apple's voice assistant replies “if you say so."
Notably, telling Siri to take the night off is one of those requests that prompts Siri to reply in a number of different ways, such as the above, "Is that so?" and "You're certainly entitled to that opinion."
All is not necessarily well in Siri-land, though. Apple is facing not one, but two lawsuits over false advertising for the still-beta feature.
It's a rare move by Apple, which usually eschews the use of celebrities in its commercials (although one could point at the "Get a Mac" ads with Justin Long and John Hodgman, those were a) relatively unknown at the time of the first ads, b) playing characters, not themselves).
You can watch the ads below.