Jesus pronounces as "blessed" those who hunger and thirst for righteousness. (See Matthew 5:6.) When we think of righteousness, we think of good behavior, doing the right thing. It's a personal matter. You make sure that you follow all the rules. You check the boxes.
Those who hunger and thirst for that may seem, well, not much fun. They may come across as goody-goody, or self-righteous, or judgmental. They are so caught up with their rule following that they miss out on the joys of life. Maybe they think it's worth it, after all, they are promised future reward.
But Jesus does not say, "Blessed are the rule followers."
We get tripped up by the word "righteousness." It's not about following rules and polishing your sterling reputation. It really means "right relationships."
"Blessed are those who hunger and thirst for right relationships." That puts a whole different spin on the saying. And notice what Jesus goes on to talk about in Matthew 5--settling disputes, not hating people, not objectifying people, serving those who oppress you. It really is about being in good relationship with other people.
If you hunger and thirst for right relationships, you can make your own world more peaceful, and you can surprise others by not being selfish. This is the kind of attitude that will make your world a better place. When lots of people live like that, you have a movement.
If you choose to live like that, Jesus says you will be filled. That's the kind of world I want to live in.
