Very few people possess true artistic ability. It is therefore both unseemly and unproductive to irritate the situation by making an effort. If you have a burning, restless urge to write or paint, simply eat something sweet and the feeling will pass.

This quote is saying that although there are very few people with true artistic ability, it is not worth trying to become one of those people because it doesn’t make sense or help. Therefore, if one feels a strong desire to write or paint that can’t be suppressed, the best thing to do is to simply eat something sweet, and the feeling will go away.