I would agree, my jw's glass is usually half empty as well. Then I pull out the 'think on the bright side', "if you only look for the bad that is all you will see", "that's funny I see the silver lining in....." or find some feel good story of people helping people to counteract his pessimism. That might sound annoying as hell but it actually does seem to help, most of the time. Also helps to limit news time as much as you can. Nobody needs to see the news 24/7 if they want to stay sane.
I can blame it mostly on the jw's as pre jw days (before he joined the cult) he was much more of an optimist and found joy more often in little things. The jw's fill their congregations with gloom and doom on a daily basis, no wonder they are such an anxious lot.