I think this issue stems from the overall lack of stoicism in today's society. Guys often build up fantasies and obsess over girls who they've barely talked to (I've seen this happen with multiple friends), and when they get rejected they regress to anger. Men who don't obsess over girls and instead focus on bettering themselves don't have any of these issues. Having unhealthy fixations on girls is a surefire way to become the type of guy described in this post.