Why do people fall in love with someone they have no chance with and will never love them back?

because love is blind; it has no boundaries, and demolishes all reason. People will aimlessly love a person for a long time before realizing that they're not the only ones in the world, and that there may be other options for them.

Answer

Sometimes people fall in love with someone believing that they are special and have feelings for them too but then they realize that that person is not special and nothing like they thought he/she was and the love will fade and they will find someone more deserving of their love.