It can be the other way round. It is just that our society seems to encourage a focus on negativity. We're might be in a beautiful park, with wonderful autumn leaves, flowers, trimmed hedges, rockeries and the like - but straight away we notice the discarded Kentucky Fried Chicken box and the empty bottle of Coke that have been thrown on the grass. We've become attuned to noticing what we don't like rather than what we do.
You can lay a lot of the blame at the way our society overall sees things. Proventative medicine, for example, gets short-shrift, whilst a lot of people's attention is focused on their ailments. There's little money to be made out of preventing illness but billions to be made out of treating ailments.
Then we have the news media. Once again the focus is always on the negative in human behaviour. Murders, rapes, swindles, con men, bombers, bank robbers - they're featured every day. Also featured are bad traffic accidents, traffice jams and corruption in high places. Good news hardly sells at all.
Let's consider Entertainment such as TV and film. Once again it's generally about crime or something bad. Why, there must be more serial killers on current television programs than there has ever been in the whole of human history. One murder apparently is not enough nowadays.
The good news is the reality of our world. There are far more good people than bad. It is a beautiful world; we only need to notice it. The answer is to become aware - as a habit - of what is good in our lives. Focus on this, especially on being grateful for what we have. This is the way to finding ourselves ignoring more the negatvity and enjoying the preponderant goodness there is in this world.