It's not always true. It's true only when you over-do it. I.e. if you like a girl, you probably have a window in which to make a move, otherwise you'll be friendzoned and not seen as sexual material.
But if you're worried that you're not appreciated enough, stop being needy and you'll see that you are loved, normally. People will notice you contacting them less and it will make them appreciate you more if that is what you want.
We want what we can't have is the bottom line.
Here's all you have to do