I'll let you connect the dots

"But the situation with rewards is even more interesting. In a recent multiphase study, Warneken and I [the author] gave twenty-month-olds various opportunities to help. Some of the children were given a concrete reward every time they helped: a small toy that they could use to create an exciting effect, which they loved. Other children were given no reward at all, not even a smile or a thank you from the adult who simply accepted the help with no reaction whatsoever. Most children helped on five occasions, and those who did participated in the second phase, in which the infants had the opportunity to help several times again. This time, however, there would be no reaction from the adult in any of the cases. The results were remarkable. The children who had been rewarded five times in the first phase actually helped less during the second phase than those who had not been rewarded. 

This 'overjustification effect' has been documented by the Stanford psychologist Mark Pepper and others in many domains of activity and is thought to signal that a behavior is intrinsically motivating. In the case of an intrinsically rewarding activity, external rewards undermine this intrinsic motivation -- they externalize it to the reward. A behavior that was already driven by external rewards should not be affected by further rewards in this way. So not only do concrete rewards not stimulate children's helping, they may even subvert it."  - from Why We Cooperate by Michael Tomasello, pp. 9-10

"Children come into the world burning to learn. They are naturally curious, naturally playful, and they explore and play in ways that teach them about the social and physical world to which they must adapt. They are little learning machines. Within their first four years or so they learn, without any instruction, unfathomable amounts of skills and information. They learn to walk, run, jump, and climb. They learn to understand and speak the language of the culture into which they were born, and with that they learn to assert their will, argue, amuse, annoy, befriend, and ask questions. They acquire an incredible amount of knowledge about the world around them. All of this is driven by their inborn instincts and drives. Nature does not turn off this enormous desire and capacity to learn when children turn five or six. We turn it off with our system of schooling. The biggest, most enduring lesson of school is that learning is work, to be avoided when possible, not joyful play as children would otherwise believe. 

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Our system of grading and ranking to motivate students seems almost perfectly designed to promote cynicism and cheating. Students are constantly told about the value of high grades. Advancement through the system and eventual freedom from it depends on them. Students understandably become convinced that high grades are the be-all and end-all of their schoolwork. By the time they are eleven or twelve years old, most are realistically cynical about the idea that school is fundamentally a place for learning. They realize that much of what they are required to do is senseless and that they will forget most of what they are tested on shortly after the test." -- from Free to Learn: Why Unleashing the Instinct to Play Will Make Our Children Happier, More Self-Reliant, and Better Students for Life by Peter Gray (pp. 71 and 73)

I'm not sure there is much else to say except that I'm not sure I should be considered to be the crazy one for never grading or testing my children.