You want another “glitch” today, don’t you? Of course you do — the last one was too easy.
You know that rule about not using an apostrophe to make the possessive form of a pronoun? Well, it doesn’t apply to one. One isn’t a pronoun; it’s a common noun. If you want to indicate that something belongs to one, write one’s.
Not that it actually matters for this example. Here’s the thing about using one as a pronoun: even though it’s technically third person, it’s a substitute for the first-person pronoun I (when one wishes to be stuffy and formal), so it is not interchangeable with the third-person pronoun they.
The second sentence is compound (you could break it up into two shorter sentences: Bad choices make people more beautiful. Good ones leave them more ugly.), so it requires a comma before the conjunction and.
I am using they as a third-person singular pronoun here. I know some people don’t approve of that, but until/unless English gets some other gender-neutral, third-person singular pronoun for referring to people, they will have to serve.
“We live in a world where an individual’s moral choices are reflected in their appearance. Bad choices make people more beautiful, and good ones make them more ugly. This leaves people quite conflicted.”