He felt that he was taken for granted.他觉得别人对他的付出不懂感激。

take someone for granted就是指把别人的付出看作是理所当然，不懂感激。而take something for granted指把东西看作理所当然，不懂珍惜。
例句：
Teenagers tend to take what they own for granted.
青少年常常把他们拥有的东西看作是理所当然。