>>>>>The odd thing is that such a simple act as turning on a light is regarded as work. Or is it not allowed for another reason?
>>>>>
>>>>>I may be off base here, but back in the day I remember learning (or hearing) that turning on a light is an act of creation (i.e. closing the circuit to create light). So, the act of not turning on the light honors the fact that no creation/work took place on the 7th day.
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>>>>>Perhaps someone else might be able to clarify.
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>>>>The act of turning a light on is falls under the heading of work and so is not allowed - the spirit of Shabbos is that we should refrain from doing all those things that we associate with our workday lives
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>>>So there's no other reason?! Then the remaining question is why it's regarded as work. Personally I do not associate it with my workdays.
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>>I believe the issue is the spark that gets created when you flip the switch. That's "making fire," which is one of the kinds of work that's prohibited.
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>I still don't get it. Although it's good to know, it does not shed another 'light' on the issue. The issue remains: Why is this (causing a spark, causing a mini-fire) regarded as work. I guess that also implies that lighting a cigarette is associated with work?

I can't say for sure, but I am almost 100% believe that your guess is correct. What is 100% sure is that you cannot carry umbrella or anything else. You cannot carry things though you can push them. It is permissible to use simple mechanical devices, e.g. play chess using mechanical clocks, but not electronic ones.
That's how any rule works. You make it one day and then you either follow it, or not; and if you follow then the initial idea, whatever it was, will get blurred anyway. If it is done ages ago then the idea will likely become unrecognizable. Does it make it senseless? Not necessarily, because the idea really existed and some people, likely knowledgeable, followed it before. If you are the person to stop, then burden is on you to start something better than it was done by previous generations, and this could be difficult.