I just finished Fable 3 and I'm pissed. Long story short; I got screwed when the game advanced too quickly and removed my ability to choose how to finish the game. Rest of this post contains broad spoilers about the structure of the game and the main events. I don't think it'd ruin the game for you, but if you want to play Fable 3 with no idea what happens, stop reading. (Personally I give the game a 3 out of 5, definitely skippable.)
The main story arc is in two parts. Part 1: develop as a hero and overthrow your brother, the tyrant king. Part 2: become the king and make a series of difficult choices. The choices in part 2 are interesting: you can either do the good thing (say, making a lake a nature preserve) or doing the evil thing (draining the lake and strip mining the lakebed). The catch is the evil thing makes more money for your treasury and you're told you have 1 year to save up enough money to build up defenses against the Big Bad and save your people. There's even a handy counter: days remaining, money needed to save people.
I liked the second part of the game, it was nuanced storytelling and required making actual difficult choices. (Presented to you by your secretary Hobson, no less). It also presents a pretty bleak moral view of the world, that leaders have to be jerks or else their people die. But ok, I can go with that. And I had a trick! I did all the goody two-shoes choices, spending all the money. But I had my own personal real estate fortune. My plan was to make enough money off of rent to cover half the kingdom's needs, then sell all my real estate to make up the rest and save the world! So clever.
Then I got screwed. I'm sitting there with 121 days to go, doing my story, when I turned in a quest and suddenly a big SAVING appeared on the screen. Then I'm teleported to the Narrator telling me my time is up, I'd made my choice, and all my people are going to die. No warning, no chance to tie up loose ends, no chance to use my money to save my people. I still had 121 days left, wtf? And the game doesn't keep old saves, so no way to go back and undo the damage.
I finished the game. And got a big rewarding speech about how I was a hero and saved the kingdom. Followed by a popup text saying I was a scoundrel and the few remaining people left alive all cursed my name forever more. Now the kingdom is largely empty, no NPCs wandering around, and my game is essentially over. Reading comments online I'm not the only person to have been tricked this way.
Two big mistakes ruined Fable 3 for me. One was triggering the endgame sequence without warning. The other was not having any way to go back to a previous save. Both are really amateur mistakes to make in a game that's supposed to be so polished.