If it comes back to you, it's yours forever. I don't know who originally came up with these phrases but I encountered this concept many years ago and I have thought about it every now and then.
In my case, the situation normally seems to be more like "the water never boils when you are watching it". It is weird, but say, I have asked a question to a business associate by email and I really need an answer now. The answer never seems to come through while I keep wondering about it. When I forget about it and start doing something else, I notice the answer has arrived in my mailbox.
I came to realize that, when I keep thinking about something or having too much "want" in my mind, it almost seems like my energy "blocks" it from coming in. When I take my guard off, it seems to find a way to come to me.
So, that is why I brought out this "If you really want something, let it go" phrase. The more "want" I have, the more energy seems to block my "want" from reaching me. Basically, things seem to work better if I don't worry about something too much. When I let it be, it seems to happen fine. Especially when there are other parties involved.
Does this ever happen to you? I know that, on the other hand, praying for something hard does help sometimes to bring out the desired results. But sometimes, the opposite seems to be true too. Sometimes you just have to let it go and take down your energy block.