I've mentioned this before, but I'll mention it again, because it's a classic example of a crap user interface: my microwave had buttons to add ten seconds or a minute or ten minutes to the time, and when you pressed them it beeped. The trouble was that the beeping seemed to be independent of how much time had been added to the quantity displayed on the difficult-to-read low-contrast display. So you'd press the button three times, it would beep three times, but you'd look at the display and find that 50 seconds had been added instead of 30 seconds. What is the point of having an audible feedback (which, by the way, was a really ugly sound) if the sound generation is mysteriously independent of the actual function being invoked? Seriously?

I used the past tense because it broke recently, which gave me an excuse to totally disassemble it. A large proportion of the total weight of the device seemed to be in one large transformer. There was a high-voltage capacitor which, according to the label, contains an integral bleeder resistor, which is just as well as I hadn't really thought about that before handling it. The bit that makes the microwaves is really cool: it looks like part of a 1960s sci-fi ray gun or a dalek's exterminator.