A: I wonder what I should eat tonight.
B: Don't sweat the small stuff. You have way more important things to worry about.
- He was too busy with his job to worry about trivial things like picking out a gift for his wife.
 the small stuff trivial things trivial matters petty things
別擔心芝麻小事 = Don't sweat the small stuff = Don't worry about trivial things = Don't worry about trivial matters