If we ever wonder why, particularly in contemporary society, few people really learn to trust living in the Now, it is because our ego doesn't let us. It runs away into stories in the midst of the abysmal feelings. The survival value that being really present offered our early ancestors (who were constantly alert to the wilds of nature) no longer pertains to the vast majority today. For us, survival is fleeing any threatening feeling while always relying on intellect to organize for the future. This leaves us living in a world of thinking and emotion. It is why modern people are generally more stressed and unhappy than people from simpler cultures who live much closer to nature. 
~Richard Moss