Remember that Gandhi quote that's like "Be the change you want to see in the world?" While the Greta Thunbergs of the earth are carrying the heavy load of the pressing issues (you know, like mass extinction), the majority of us are out here doing God's work in the only small ways that we know how.
Whether you're helping an old lady across the street or letting your boyfriend have the last pizza slice even though he totally had more slices than you, your small acts of bravery will eventually amount to positive change.