Art is the attempt to take an idea or ideal and make it manifest with no compromise.

To the degree that the person can brook *no* compromise they are that much of an 'artiste'.
When the slightest deviation or compromise from the idea or ideal is experienced as a deathblow to the soul then you know you have a true artiste. Ergo the 'tortured' artist.
A lot of endeavors are actually an artform - depending on how they are undertaken - the intent and the motivation(s).