Exaggerate trifling difficulties, as in If you forgot you racket you can borrow one—don't make a mountain out of a molehill. This expression, alluding to the barely raised tunnels created by moles, was first recorded in John Fox's The Book of Martyrs (1570).

To blow an issue or event out of proportion: “You have only a small blister on your heel, but you complain as though you broke your leg. Why are you making a mountain out of a molehill?”