While I know it isn't feasible to go too far in depth, the historical background is extremely rich on John. The reference to "The Word" and Light would have meant a lot to John's audience that we miss. But both speak to the way people were trying to makes sense of the world in John's day. Jesus is THE WORD (the force that brings order to the universe) the LIght (the SOURCE of life) and the MESSIAH (the Savior the prophets wrote about.)
When we are introduced to the disciples the theme becomes "we have FOUND HIM." We have found the one we (and others) have been looking for. I really get the impression that the men Jesus called were those who had been searching and spent time discussing that search. So when Jesus found them, they went to find others who had been searching. Not everyone is that serious about the search, and unfortunately, many settle(d) for cheap imitations. "I am a Jew, or a Pharisee or a Gnostic or ascribe to this or that philosophy. Good enough, I will pay my dues and be a good member in standing." It is tempting to "cast a broader net" so those who are not that serious about the search don't go away. When Jesus encountered Nathaniel he praised his healthy skepticism. No imitation Messiah would do. As we proceed through John we see that occasionally Jesus "thins the herd" by intentionally discouraging those who are not that serious.
John Mayer has a song, "Who do you love?" He asks, Who do you love, me or the thought of me?" Jesus asks a similar question: "Do you love ME or the thought of me?"