Keeping your heart pure and upright in the sight of the Lord is the most important thing to Him. Focus on the things of God, and not of this world. You will start to feel your desires shift the closer you get to Him. The work you do for His Kingdom is not in vain, it will all be worth it in the end.

Matthew 25:21
"His lord said unto him, Well done, thou good and faithful servant: thou hast been faithful over a few things, I will make thee ruler over many things: enter thou into thy joy of the lord."