Kogasa suffers from self-esteem problems, as she is easily pushed into lamenting about wondering what her purpose is, or that she might be better off if she just went back to being an umbrella. Perhaps due to this, Kogasa is seeking a true purpose of existence for youkai, tsukumogami, and herself. She attempted this by starting a career in babysitting (which did not seem to go very well), surprising people (which also isn't going very well, and was even considering going back to being an umbrella just so she can be useful in that regard. She's stated that she's trying to imagine what humans want, and then plans on becoming that something they can use.[1] Deep down, it appears this pitiable illegally dumped object and troubled forgotten item just wants to be desired.
Her depression may also be another attempt at getting attention. She can get so depressed upon failing to surprise someone that it can become "a bother". In Undefined Fantastic Object, Reimu Hakurei wonders if Kogasa just wanted to be beaten up. That Kogasa ironically treats umbrellas like garbage by throwing them in certain spell cards leads Hatate Himekaidou to wonder if she wants to be treated like garbage, herself.
Unlike other youkai, Kogasa doesn't eat humans. Instead, she eats their spirit. In her own words, if she doesn't surprise someone, she'll go hungry. In the past, humans apparently feared youkai enough that she'd get a huge portion of their spirit on a successful surprise, as according to Kogasa in Undefined Fantastic Object, even a slight surprise would make a human have difficulty walking straight. This is apparently no longer the case in the present day.
