How does teaching of Buddhism deal with waste? How does teaching of Buddhism deal with acceptance even it causes unhappiness?
If you don't want or don't need something that you have, donate it or give it away to others who need it, instead of throwing it away.

Donating to monks or virtuous people is better than donating to unvirtuous people. But any kind of donation, even to animals, is a source of merit.

From AN 3.57:


  "I tell you, Vaccha, even if a person throws the rinsings of a bowl or
  a cup into a village pool or pond, thinking, 'May whatever animals
  live here feed on this,' that would be a source of merit, to say
  nothing of what is given to human beings. But I do say that what is
  given to a virtuous person is of great fruit, and not so much what is
  given to an unvirtuous person.


Wastage of things and wealth in Buddhism is not about throwing things away. Rather it's about not using things and wealth for the benefit of oneself and/or others.

From SN 3.19:


  "That's the way it is, great king. That's the way it is. When a person
  of no integrity acquires lavish wealth, he doesn't provide for his own
  pleasure &amp; satisfaction, nor for the pleasure &amp; satisfaction of his
  parents, nor for the pleasure &amp; satisfaction of his wife &amp; children;
  nor for the pleasure &amp; satisfaction of his slaves, servants, &amp;
  assistants; nor for the pleasure &amp; satisfaction of his friends. He
  doesn't institute for brahmans &amp; contemplatives offerings of supreme
  aim, heavenly, resulting in happiness, leading to heaven. When his
  wealth isn't properly put to use, kings make off with it, or thieves
  make off with it, or fire burns it, or water sweeps it away, or
  hateful heirs make off with it. Thus his wealth, not properly put to
  use, goes to waste and not to any good use.
  
  "But when a person of integrity acquires lavish wealth, he provides
  for his own pleasure &amp; satisfaction, for the pleasure &amp; satisfaction
  of his parents, the pleasure &amp; satisfaction of his wife &amp; children;
  the pleasure &amp; satisfaction of his slaves, servants, &amp; assistants; and
  the pleasure &amp; satisfaction of his friends. He institutes for brahmans
  &amp; contemplatives offerings of supreme aim, heavenly, resulting in
  happiness, leading to heaven. When his wealth is properly put to use,
  kings don't make off with it, thieves don't make off with it, fire
  doesn't burn it, water doesn't sweep it away, and hateful heirs don't
  make off with it. Thus his wealth, properly put to use, goes to a good
  use and not to waste.