When I go around finding flaws in everything, I stop enjoying it, and living a life where I can't enjoy anything I read or hear or see is not pleasant.

Having recently posted on the relevance of Pope's poetry to rationalism, I can't help quoting him one more time here:

Avoid extremes, and shun the faults of such
Who still are pleased too little or too much
Those minds, like stomachs, are not always best
That nauseate all, and nothing can digest