I used to complaint that, when I come to this world, that my parents owes me, after I come out to work, I have high goals, back in 1990's my dream is to build a robot, this is due to I have heart ❤ broken a few times, back then, Artificial Intelligence does not exist, one day I cried at night knowing I'm unable to continue my studies to Degree. After sometime , I found my wife.
The thing is that, do not give up in your dreams and do not complaint, you think what you become.
Don't feel sad, living in the past, that you can't change, it is a waste of time and you are not growing. Let it go, and make yourself useful, take responsibility of your action, and change for the better.
When a person give you a big plate of food, and you can only eat a bit, of course you would not suffer yourself to eat all of it. Sometimes people won't understand your needs, you only choose or take what you want.