For any lifelong vocation that we take on, there will be different challenges and sacrifices, just as there will be particular rewards and joys.
When Jesus asked the rich young man to come follow me, he asked him to give up the one thing that he was in love with most, the one thing that was really getting in the way of him developing a loving, committed, freely giving relationship with the Lord - his money.
Jesus was asking this young man to be detached from that one thing that was enslaving him, that took the focus of his whole life, that was not allowing him to be free to live life to the full.
So, to be a Priest, or a Brother, or to be Married, or a Sister, or living a dedicated Single life, all require us to go beyond those things that would entrance us and enslave us to living a narrow, small, and insignificant life, rather than to do something great for God.
Beyond this, if a person's call is to be a Priest, then there will be particular challenges specific to this calling. For many these will be in the area of sacrificing the joys of married life for a life that is lived in a Community (for a Religious Order Priest), or alone (for a Diocesan Priest).