Chris Long writes about being allergic to cynicism. He explores where cynicism comes from (a failure to live up to a personal or institutional ideal, probably) and what is so dangerous about it. In a sentence: 

“Cynicism starves the metabolism of an organization. Habitual cynicism calcifies into institutional inertia. It is debilitating at an individual and organizational level because it refuses the difficult work of cultivating relationships based a shared vision of what is possible.” 

I basically agree with this, though I would put it slightly differently by removing it from an institutional context:

Cynicism is a lowering of expectations which often results in a lowering of an individual’s capacity for excellence.

Disappointment is a natural feeling when something that should be the case turns out not to be the case. It’s a distant cousin of, but still separate from, cynicism, which invites a person in essence to meditate and wallow in that disappointment. Cynicism isn’t pragmatism—it’s a close cousin of sloth. 

Which is what makes failure, for the cynic, something like a self-fulfilling prophecy.