A: But you can't make the world a better place unless you are critical of it. You can't make it a better place unless you first identify the things that are wrong with it.
B: But you can by just immediately believing everything's basically fine.
A: That's an incredibly short sighted solution. It's what someone would do who didn't look very far into the future.
B: It's what a person would do who is capable of enjoying themselves right now. Those who can't have no real choice but to forever focus on some distant future that will never arrive.