The act of hubris was claiming that she was equal to a god even though she wasn't, and her consequence was being turned into a spider.
The Story of Arachne By: Mary Elizabeth Siachos
The plot was that she bragged about being equal to a god which caused Athena to visit her and prove she was wrong, by turning her into a spider.
Arachne bragged about how her weaving is equal to Athena's.
I am famous for the finest thread and weaving, even Athena could not beat me
This myth applies to modern day children, because they think they know everything and think they're better than everyone.
It causes a old lady to visit her and scold her on claiming herself equal to a god.
Reckless girl, how dare you claim yourself equal to a god.
Stupid old women, who gave you the right to speak to me that way
I challenge you to a contest to prove who is a better weaver
The old lady grew tall and turned into Athena herself, and Arachne challenge her to a contest
Athena's tapestry was bordered with and olive vine. Her favorite tree was right in the middle and one final warning was at the bottom, it was Athena herself, competing with Poseidon against the mortals who claimed themselves equal to the gods.
Never before had Arachne matched anyone who's skill was equal's, enraged by this she started weaving things that showed evil or unworthy actions of gods.
Athena was outraged when Arachne had finished the tapestry, and turned her into a spider.