Part of the challenge of making a difference in the world is finding the right problem to solve.
The world is full of problems. You can’t solve them all. You have to find something that is (a) a problem (b) that you are equipped to solve (skills, knowledge, resources), (c) that you are passionate about solving, and (d) that you can motivate others to help solve.
The alternatives:
(1) not identifying any problems at all (head in the sand)
(2) being unable to do anything about any problem (ill-equipped, ill-informed, ill-educated)
(3) being unwilling to do anything about any problem (lazy, apathetic, unpassionate)
(4) being unconnected to enough resources to make a difference (you can’t do it on your own).
Picking any problem at all is the first step; but picking the problem that is the match for your abilities is crucial if you are to succeed.
(Of course, abilities can change, if you are truly passionate.)