The media have a lot to answer for - celebration of good news (other than 'feelgood' stories or sport achievement maybe) is low priority as it doesn't increase sales. Every day then, the media reinforces the premise that we should only be interested in bad news. This conditions our mindset in the way you describe and the pattern is the same now in many countries. Its powerful stuff, so we should be wary of a tendency to place media control into the hands of a just a few players.
Sadly because when you do something wrong or mess up in life people have a tendancy to remember that instead of all the good you have done.