These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Base Breaker: Fans are divided over whether Reaver is a hilarious and awesome character (and voiced by Stephen Fry) or if he seriously needs to finally get some comeuppance for his bad deeds, particularly for making Fable II's Player Character give away his youth (if the player chooses to be good) and killing Barnum.
Designated Hero: Played with in Fable II. Since you're The Chosen One, pretty much all of your "moral lapses" are forgiven, simply because it would be far worse to punish you and put you off your destiny. Same with III, if you are not the ruler of Albion when darkness incarnate hits, everyone loses.
Fridge Brilliance: Some people have made a fuss about death just being a slap on the wrist in Fable II and Fable III, but the sheer brilliance of it is that no matter how powerful you are, you're not guaranteed a happy ending, especially in Fable III. In other words, death is not important - your decisions are. You're a Hero.
Spam some of the Will powers and the enemies won't even touch you. Lampshaded when some bandits shout out remarks along the lines of "How the Hell are we supposed to fight against that?" as you're frying them from the inside out.
Plug in a second controller in Fable II. Start co-op mode without a gamer profile or using an existing save to load an equivalent power henchman. Discard the henchman's abilities, and then leave co-op mode. All that free xp you just gained from discarding the henchman's skills is now yours. Rinse and repeat, as the henchman gets more powerful each time!
Being a landlord in Fable II makes your ascendency to insane riches laughably easy. Within a few hours a player can afford to buy all the property in the game and becomes so ridiculously wealthy that any money made through adventuring is effectively redundant. In Fable III this is still the case, and in fact the only way to achieve the Golden Ending (all "Good" choices as a monarch, maximum army strength) is to become a land baron.
Goddamned Bats: Goddamned Shadows. Goddamn Hollow Men. The third game adds actual bats to trouble you but they are so easy to dispose of they're more like set dressing.
"Try to get your combat multiplier even higher," in the first game.
"Your health is low." This was Lampshaded several times in the sequel: one of the loading screens states that there is a rumour that shortly after the first game's villain was defeated, the Guildmaster was found dead with the words "Your health is low!" carved into his head. There's a potion shop in Bloodstone called "Your Health is Low." Additionally, an assassination contract calls for the murder of someone who dresses up like the Guildmaster and says, "Your Health is low, do you have any potions?" to the annoyance of everyone.
The Gargoyles also use the "your health is low" phrase as well, though thankfully, you can shut them up.
Well fortunately that one can be turned off. What can't be turned off (short of modding the game) is the incredibly grating buzzing sound the mana shield spell makes for as long as it is active.
"Keep hitting it like that." "Hit the blade, not the anvil!" "The anvil doesn't need forging!" "You know how to use a hammer." Throws me off every. Time.
"Shops are now opening!" Annoying when you're trying to concentrate on your blacksmithing, at least.
The dog in 2 & 3. You walk up to a chest straight in front of you and then your dog barks and has the little treasure symbol above his head! "Where, boy? Where could the treasure possible be?"
There's also the taunting gargoyles, but they're supposed to be annoying.
And the third game brings the gargoyles successor, the gnomes, which is hinted at in the mission where you give them life; the item used to transform them from lifeless garden gnomes is caused by a gargoyle that looks identical from the ones in the second game. They're considerably more horrible than gargoyles, as gargoyles were just insulting; the gnomes downright threaten you.
Narm Charm: Every last person in Albion have either British or Irish accents and they're very stereotypically exaggerated.