Meditations 7:67

Nature did not blend things so inextricably that you can't draw your own boundaries—place your own well—being in your own hands. It's quite possible to be a good man without anyone realizing it. Remember that.

And this too: you don't need much to live happily. And just because you've abandoned your hopes of becoming a great thinker or scientist, don't give up on attaining freedom, achieving humility, serving others, obeying God.