fly in the ointment

[fly in the ointment] {n. phr.}, {informal} An unpleasant part of apleasant thing; something small that spoils your fun.

We had a lotof fun at the beach; the only fly in the ointment was George's cuttinghis foot on a piece of glass.

Your new job sounds too good to betrue - interesting work, high pay, short hours. Isn't there any fly inthe ointment?