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.
YMMV: Guards! Guards!
Fridge Brilliance: Vetinari actually started most of the conspiracies dedicated to his own overthrow, so he could keep tabs on them and sabotage their efforts as needed. He also has spies monitoring the Guilds, the nobility, the criminal community, and anyone else of influence. The only reason the Elucidated Brethren's plot managed to hold together long enough to cause trouble is that the Supreme Master deliberately recruited its membership from the least important people in the city: low-grade, workaday craftsmen and laborers, whom even Vetinari hadn't thought it necessary to spy on.
Re-read the Brethrens' complaints about being "oppressed", and notice how they sound like henpecked husbands who are always being nagged at by women. Small wonder, that the dragon they summoned to terrorize the city turned out to be female.
Magnificent Bastard: This is the novel which really creates the character of Vetinari in this way.