schwarzsehen
to be pessimistic; to look on the dark side, fear the worst
Origin
Black is the colour of misfortune and gloom; someone who 'sees black' pictures the future as dark and expects the worst. (To be distinguished from 'schwarzsehen' in the sense of watching TV without paying the licence fee.)
Building blocks
Words in this expression
Examples
Sei nicht so ein Pessimist – du siehst .
Don't be such a pessimist — you always look on the dark side.