A number of years ago, I listened to an audio program by Mike Wickett, and in that program, Mike said something that really struck a chord in me.
What he said was along the line of, "The universe is like an echo. Whatever you say to the Universe, it will repeat back to you. If you tell the Universe you don't have enough, the Universe will tell you that you don't have enough, and will back it up with experiences to prove it. On the other hand, if you tell the Universe you have more than enough, the Universe will repeat that back to you, and back it up with experiences to prove it."
One of the biggest stumbling blocks for many people is breaking out of a pattern of lack and limitation. They get into this pattern, and then they hold on to what they have even tighter, afraid that if they let go and release it into the Universe, it will be lost and they will be left with nothing.
The problem with this is that the more they hold on to what they have, thinking that they don't have enough, the more the Universe reflects this idea back to them, with experiences proving they don't have enough.