Our mood or state of mind has a serious effect on not only how we interpret a scene, but also what elements of that scene we actually pay attention to and 'notice' in the first place. (There are piles of empirical evidence for this in the annals of psych research.)
It is also clear that the effect is to re-enforce and justify the mood we are currently experiencing. It's like our mind is looking to match the feeling we have with events in the world. In essence, finding proof that our mood is justified.