Why is Shay so angry with Tally in the Smoke?

Shay is angry with Tally because she feels betrayed when Tally turns her in to the authorities. Shay had trusted Tally with her secret plan to escape to the Smoke, and she feels betrayed when Tally goes back on her Word. Additionally, Shay is frustrated with Tally for choosing to conform to society's expectations rather than supporting Shay's desire for freedom and independence.