Every time he sees a small problem, he acts like there's a fly on the nose.
Каждый раз, когда он видит маленькую проблему, он ведет себя так, как будто у него муха на носу.
Definitions
A 'fly on the nose' refers literally to an insect landing on someone's nose, but it is not a common idiom in English. If used figuratively, it could describe an annoying or distracting presence that is hard to ignore, similar to how a fly on one's nose would be bothersome.