Matthew 5 lists 9 declarations of the blessedness of those who follow Christ. These 'B-attitudes' are difficult to grasp because each statement identifies people who are characterized by difficulty, struggle, and hard work. 'Blessed' involves being fulfilled, gifted, joyful, and blessed.
When are we blessed, or feel blessed? Present tense is seen in vss. 3 & 10. Future tense is seen in six declarations. "When"-ever you are reviled and persecuted for Christ's sake is in vs 11. Future and past tense is seen in vs. 12. "Rejoice and be exceedingly glad, because great is your reward in heaven, for so they persecuted the prophets who were before you."
Let us choose happiness because it is a command. Let us focus on God's promises so that we can feel happy in this life. Keep looking forward to God having the final say in rewards and judgments. Be happy because the reality of happiness & blessing is completed in eternity no matter what happens temporarily in this world. Be regularly restored to a joyful heart by daily confession of sin(s) as David prayed for in Psalm 51. After repentance and confession, pray, "Restore to me the joy of Your salvation, Lord." Finally, maintain that positive faith attitude by remembering the temporary results. Psalm 15:13-15 teaches us that a joyful heart produces a cheerful face, a healthy spirit, and mental nourishment. It is good like a medicine, and gives physical healing and strength as well.
In this life, the sad, discouraging things are real and repeated. We don't pretend; we just choose to see God as more powerful than these realities. We see God as eternal, and these realities are not. We know our God is so good and wise, He makes us more like Jesus as He mixes "all things together for our good."