Considering that a "random mp3 player" costs $6 on Amazon and that an Apple iPod costs over $200, I'd say people are totally justified to get upset. They spent the extra money expecting a product whose quality matched its price.
I'd say this is true of cars as well. When your used Ford Escort breaks down, you're hardly going to be surprised. When your exceedingly expensive Tesla breaks down and/or catches fire, you're going to be a tad upset.
That said, I'd say people lose all rights to be upset when they are the cause of the malfunction. You can't be too upset at a broken iPod after you drop it down a flight of stairs, and you can't be too upset at your Tesla catching fire after you ran it into a tree at 110 MPH. (I'm not saying the Tesla driver was upset mind you- I think all the Tesla hate is just coming from frightened car manufactures and the media.)