If we look at this with respect to neuroscience, this is absolutely true. Our limbic system keeps us away from pain. So if there's something we desire, there’s something about it that we also fear because it is essentially something we’ve never experienced before. Example, we want to lose weight. This is our goal. So even if we work towards it, our limbic system keeps us away from fully achieving this goal because it doesn’t know if being “thin” is going to feel better than being “fat”. Will you really enjoy giving up all the foods you love to look thin? Will you really feel good eating only boiled foods? Will you really be happy with this new lifestyle if it means you can’t freely hang out with your friends who all eat choose to eat fast food when they get together? All these “fears” keep us from our goals.