Each week of 2017 we present an English idiom.
"to make a mountain out of a molehill": to treat something that is unimportant as if it is extremely important (aus einer Mücke einen Elefanten machen)
Example 1: The new clients are arriving in 30 minutes but Lena is giving the presentation and is stuck in traffic? Let's not make a mountain out of a molehill. We'll make some adjustments to the schedule. We can introduce them to the key people in manufacturing and do the factory tour first. By the time we're done with that, Lena will probably have arrived.
Example 2: Your boss said you made some mistakes and need to pay more attention to detail? No need to make a mountain out of a molehill. I'm sure you'll do better next time!