What is the central idea of the life isn't fair-deal with it

That not everything goes you're way and you have to live with it

"Life isn't fair. Deal with it." is a saying that often brings people back to reality. Some are born rich, some are born poor, some are boor disabled. Some are able to change their destiny, some die early because of others. We can't have things our way all the time. We rarely do. Life is chaotic and we just have to learn to navigate the best way we can and accept that not everything is under our control, because things are not really under our control.