See.

What one has most to work and struggle for in painting is to do the work with a great amount of labour and sweat in such a way that it may afterwards appear, however much it was laboured upon, to have been done almost quickly and almost without any labour, and very easily, although it was not. A beautiful thing never gives so much pain as does failing to hear and see it. If people knew how hard I worked to achieve my mastery, it wouldn't seem so wonderful after all.
- Michelangelo

Thanks Cultural Offering.