Recently, I read UFO ReimuA's story again, I think Kogasa's past is interesting. She wasn't thrown away, her owner forgot to take her then no one have picked her up because of her unpopular color, that is the interesting part. Her color is purple, for a object like umbrella dyed purple, it means the owner or creator might appreciate it or it was indeed expensive, because that time, purple dye was rare and costly, moreover it is symbol of aristocracy. So I guess her owner might come from a noble or rick family or a famous artisan. In WaHH, Kogasa is recognized as a talent artisan and blacksmith, because of her creator or she is just that good, she has lived for more than a century, a hard working and pursuit youkai so it is understandable.
A normal tsukumogami usually hold great hatred toward human but Kogasa doesn't, I think she was a loved umbrella and the reason why she turned into a youkai not because of hatred but self-pity, nothing more than a decorated umbrella, not a useful tool. The reason no one picked her, I think because the lower class people didn't understand her value. In UFO, she told Reimu:
"But the pointlessness is what's really beautiful. It would be terrible if everything in life were all planned out.
Even tools aren't beautiful just because they're functional. The useless parts are what make us youkai ..."
I think she roasted Reimu that she is just a boor pitch who will never under stand her (Kogasa's) true value. In ReimuB's scenario, Reimu said:"Maybe you're luxury items?", so my assumption above proved what Reimu said is not random.
It took a translator more than a decade to realize "skyscraper" in Emotional Skyscraper ~ Cosmic Mind doesn't indicate a skyscraper but a triangular skysail, and it took me years to understand that Kogasa roasted Reimu in UFO.
...Her color is purple, for a object like umbrella dyed purple, it means the owner or creator might appreciate it or it was indeed expensive, because that time, purple dye was rare and costly, moreover it is symbol of aristocracy.
I'm not sure for the Japanese Imperial Family, but I think that in China, purple was exclusively for the Emperor, so Kogasa is very, very posh.
I think she roasted Reimu that she is just a boor pitch who will never under stand her (Kogasa's) true value.
Reimu's behaviour in most canon sources paint her as excessively materialistic: her perpetual frustration regarding her finances, and her unwillingness to put in any extra effort other than short-term ploys that never solve her financial situation durably, are clear indication she doesn't value things like hard work and dedication (well, that one isn't really news to most fans), only money and material possessions that serve a direct, useful purpose. Which is very unbefitting of her position and job as a shrine maiden.
No wonder Yorihime beat her so effortlessly in what is supposed to be her speciality: Reimu severely lacks genuine spirituality.
Image looks nice, thought it was the usual kogasa being defeated...then i saw that her real body, aka the umbrella, was broken and I realized....you just killed her XD