surely this malaise has stopped a thousand brilliant would be artists and creative types form actually achieving their dreams - surely its worse than a lack of confidence.

Peter Cook suffered from this - Kevin Shields probably does and many many others who I expect you knowledgeable lot to mention (barring J Mascis thank you).

"There's nothing worse than ennui, Dorien" - Oscar Wilde, The Picture of Dorien Gray. His most haunting line if somewhat non-epigrammatical.