Night Watch (2002), by Terry Pratchett.

> People on the side of The People always ended up disappointed, in any case. They found that The People tended not to be grateful or appreciative or forward-thinking or obedient. The People tended to be small-minded and conservative and not very clever and were even distrustful of cleverness. And so the children of the revolution were faced with the age-old problem: it wasn't that you had the wrong kind of government, which was obvious, but that you had the wrong kind of people.

Additional context: The city is being (mis-)ruled by a paranoid dictator, whose brutal secret police don't care too much about if you're innocent. The cynical protagonist is frustrated that some of the resistance is also extremist or at least overly-optimistic about what's going to happen next.