I think that Lilmod’s point is well made, and well taken. There are many shailos that people (including myself) don’t even think to ask.
However, looking at Lilmod’s lists of questions, I think there is another aspect at work here. I, and I suspect many others, have an aversion to asking shailos. As such, I simply avoid questions or I am machmir when it is not too difficult to do so.
For example, because I don’t know what the proper halacha is if I am planning on eating potato chips in two locations, I simply do not eat the potato chips in the second location. I am pretty sure that having Shabbos candles on a shaky table is bad idea, so I would simply not put Shabbos candles on a shaky table (as a general practice I don’t think it is good idea to put Shabbos candles on the table because of bosis).
As an aside, the best practical hilchos Shabbos sefer, in my opinion, is Rabbi Ribiat’s 4 volume set. He really does cover almost every practical scenario and he has extensive endnotes so you can look up the original sources.