Quoted: Einstein On Insanity

Albert Einstein didn't officially ply his trade in marketing (he chose to go the theoretical physics route), but he is widely regarded as one of the most influential intellectuals of all time--and for good reason.

Consider his insightful and succinct definition of insanity that can apply across business and academic disciplines, but has merits in the field of psychology and branding (asking 'why we buy?'): 

The definition of insanity is doing the same thing over and over again and expecting different results.