It gives people something to look up to, give them inspiration and strength to do/pull through things, albeit good or bad. Some people use religion as an excuse to start wars, I think others just care so much about it they believe that what they are doing is the right thing.
I'm not religious and don't believe in God etc so I can't give opinion on what it's like to be religious, but to me religion is just like a.. erm, diet? They tell you what to do and what not to do and you live on those rules.
Most people turn to religion when they have nowhere else to go so I guess it's good in that aspect but bad on many other levels.