unnecessary sound

so recently i've noticed that in a lot of the things that i've been watching that they include a lot of unnecessary sound or sound that would not normally occur. a few example that i can remember is a scene in which a family is eating dinner and the father picks up a piece of silverware and you hear the sound of clanking silverware. in most everyday situations you would not normally clank your silverware together before you pick it up. another example i can think of is that i was watching a show about magnets on the history channel or something like that and they were showing how you can make a magnet my wrapping wire around a nail and connecting the ends of the wire to a power source and in the illustration of how to construct such a device they had the sound that everybody associates with a electricity, the buzzing sound. even though if you actually made this kind of magnet in real life that it would not make this sound and in fact would have to be an incredibly high voltage to actually make anything like this sound. and they did this even after they had already highlighted the wire blue to show that it had electricity running through it. i guess that this is done to focus attention to a particular thing in a shot, but many times it seems like attention is not needed on that particular thing. it generally doesn't have anything to do with the plot. i remember a number of years back hearing about how a lot of things in film are over exageratted because the audience can be kind of dumb sometimes. the thing that they cited as an example was the visual use of over empahsizing things with putting ribbon on to fans or air conditioners to show that they were actually on, because if the audience doesn't see that the air is moving they don't think that it is actually on. so i guess that this over use of sound is the audio version of over emphasizing.