Why are ideals and reality often opposite?

The ideal world is a perfect and beautiful world, but the real world is indeed a real and cruel world. When the ideal and the reality are infinitely close, the beautiful and real world will slowly emerge. On the contrary, the heart will be broken, the beautiful dream will become the bad news of life, become the weight of life we can not afford.

About ideal and reality, the philosopher Feng Youlan summarized a few points, let's listen to see what are the advantages or disadvantages.

1, Siddhartha Gautama cut his own flesh to feed the eagle, is an act of mercy, but with the blood and sweat of the Indians, to maintain the prosperity of the British, not only Gandhi opposed, even if Siddhartha resurrected, will not agree. The British ideal is nothing but profit.

2, between countries would not have any law, and will not talk too much about morality, between countries there is no eternal enemy, only eternal interests. It is better not to talk about ideals between nations, but about reality.

3, ideals and reality are not opposites, but dependent on each other. Reality cannot be separated from ideals, and ideals cannot be separated from reality.