Book Reports / Similarities or Differences between Hamlet and The Great Gatsby [3]

so i have to do a comparative essay on my english exam tomorrow , and i have thought of a thesis, but when i asked my teacher about it, he said that on the exam i might to have to make a small change to my thesis.

i've been trying to think, but i can't come up with anything that i would make me change my thesis and points only a bit.

so can you please take a look at what i have and maybe give me some suggestion as to maybe what my teacher might change the theme to?

thesis: In Shakespeare's Hamlet and Fitzgerald's The Great Gatsby, the characters' decisiveness work against themselves, thereby leading to their demises.