glass half empty
Of or characterized by a generally pessimistic worldview. (Typically hyphenated and used as a modifier before a noun.) Mark is such a glass-half-empty kind of guy that he will find a way to see even the best situation in a negative light. When it comes to the state of the world, most people are glass half empty. But they forget all the progress that has been made.
(see the) ˌglass half ˈfull/half ˈempty
used to describe whether somebody has a positive or negative attitude towards something: People are prepared to see the glass half full at the moment rather than half empty.He’s a glass-half-full type of guy (= he always expects good things to happen).