Do we know too much to ever be completely content?

Human beings are intellectually distinct from other animals. We are intelligent to the degree that we are able to question our existence. We also know that we cannot find the answers to these big questions, perhaps because some of the answers are found in dimensions we cannot conceive of. So no matter how much an individual enjoys their life this underlying uncertainty regarding the purpose of their existence taints that enjoyment (and I think religion is a solution to this for some people). Do you think we would be a happier species if we knew less?