cunning people are like suicide bombers. they blow themselves up to hell and destroy the lives of people amidst whom they live. almost always, these are the very people who love them most (family/friends).
fortunately, nature has a sense of balance, and tends to favour the innocent. for, although they suffer injuries inflicted by the too-clever people, they are rewarded with wisdom (from the experience) and happiness (wisdom, NOT ignorance, is the actual source of bliss).
and what of the schemers? like all villains of popular fiction, they end up getting their just desserts: friendless, alienated from family, lonely and pitiable.
...oh wait, let me correct myself: they WERE friendless, alienated from family, lonely and pitiable all along. because 'clever' people are too wrapped up in their schemes to notice that they are actually loved and wanted by their family and friends; that they don't need to 'earn' these with their clever plans.
ah, if only people were sensible (not 'clever') enough to realise that being honest to themselves is all it takes to be loved...