Most Helpful Guy
It is a good idea to separate, in your mind, the reality of someone and the IDEA of someone. If you never really got around to saying hi to someone then you have to question how well you really knew them. Until you have spent serious time with someone, and have talked in depth, then you really don't know what kind of person they are. You can build up a perception of them in your mind but it's not necessarily who they actually are. In which case, you are building an image of someone based on what you want them to be which, in turn, suggests a longing within you that is not necessarily attached to any one person.
You might come to realise that this was not so much about HIM as it was about your desire to have someone in your life, someone that makes you feel happy and excited to be alive. Once you realise that then he will lose a certain amount of power in your thoughts.