Velazquez found the perfect balance between the ideal illustration which he was required to produce, and the overwhelming emotion he aroused in the spectator.
Too much polishing and you spoil things. There's a limit to the expressibility of ideas. You have a new thought, an interesting one. Then, as you try to perfect it, it ceases to be new and interesting, and loses the freshness with which it first occurred to you. You're spoiling it.
The enthusiast always finds the master, the masters, whom he seeks. Always genius seeks genius, desires nothing so much as to be a pupil and to find those who can lend it aid to perfect itself.