By You can’t fix all the problems of this world, but you can fix all the problems of this world that manifest themselves in your own convictions, values, thoughts, actions, and words.
The world has a big problem with entertainment, but you can maintain the balance of godly enjoyment and relaxation (Eccl 2:24-25).
The world has a big problem with lazy under-productivity and over-stressed under-productivity, but you can maintain the balance of godly work (1 Thess 4:11-12).
The world has a big problem with injustice and suffering, but you can love your neighbour (Lk 10:30-37).
The world has a big problem with marriage and sexuality, but you can prove marriage to be honourable and sexuality to be pure (Heb 13:4).
The world has a big problem with wealth/poverty and possessions, but you can be content in whatever situation (Phil 4:12-13).
You can add any other big problem that is always part of this world, and you will find a good godly Christian response to it in the Scriptures. The world that you are in might be full of problems, but your spot in this world can prove that the God-given answer always works. Do not therefore think like this world and act like this world, but prove instead what God’s will is and that it really does make a difference (Rom 12:2).