Why you should never give up

Each person living on this planet has developed certain needs and desires as a result of the situations he has been through in his life. While the needs of these people differ still they all have one common goal which is to fulfill their needs.
Real happiness is experienced when people manage to satisfy these needs while depression is experienced when the path that leads to the satisfaction of one of the important needs gets blocked.
An ambitious person, or a person who has a powerful need to achieve more than others, will certainly become happy if he realized his dreams while he will become depressed if he lost hope in doing that.
So what does this has to do with giving up?
The important point you should note is that you can still be happy even if you didn't satisfy your needs provided that you believe that one day you will achieve them.
Now when you give up you send an unconscious signal to your mind telling it that this certain need will never be fulfilled and as a result it responds back with depression!