The problem is, you scatter your mind. This is the general tendency of the mind - it can focus itself or it can scatter itself. Its focus is infinite, its scatter is infinite. The mind has no limit. At one time it can just beam on one wavelength, and at the same time it can work on millions of wave lengths.
Prayer is a telephone call through the universal exchange.
If the current is strong, though the distance is long, it will be heard at the other end. Help will come. If the current is weak, it will not be heard. So some people's prayers are heard and others' are not because their minds are scattered. A one-pointed mind is required to live happily on this earth.