My brother was an improviser. He's now a lobbyist, but he used to perform improv in the city when he was in high school, and one of the funniest guys I know to this day.
The golden hour of invention must terminate like other hours, and when the man of genius returns to the cares, the duties, the vexations, and the amusements of life, his companions behold him as one of themselves - the creature of habits and infirmities.