In Life we know there are girls with guy friends that they are extremely compatible with(vibe together well),who are very ambitious/interesting(has different goals/hobbies and works hard at them), and who treat their friends who are girls with the utmost respect and kindness(treating them like a human being). However in some of these friendships, the guy friend will develop feelings for the girl, but the girl will not feel the same, even though sometimes the girl will end up with a boyfriend(sometimes not so respectful or even interesting) a few weeks later. Since we know only personality matters for relationships, why does this phenomena happen? What is/are the missing piece/pieces the guy friend does not have?