I also think that is the person whom is in love with the other person in which the feeling isn't mutual, that the smitten one should respect the boundaries set up by the other.

To put it this way, e.g. My sister and a man she was crushing on way back when.

She was Obsessed in love with him and he, well, didn't feel at all the same way.

What he said to me was "It is like a one-sided magnet trying to attach itself to a fridge. Me being the fridge. The magnet's not ever going to stick."

I know, harsh, but I agree. No matter how hard the smitten one tries, the oblivious one will not come around.

It is best that the crushing one accept life and NOT lose a good friend by pushing too hard. It makes the "target" very much uncomfortable around them cause they know and end up trying to avoid contact with the "crusher".

But again, JMHO.