The likeness-leads-to-liking effect leads us human beings to like others based on their level of similarity to us. This may include but certainly is not limited to similarities in opinions, interests, and attitudes.
I remember one of my very favorite teachers that I had often giving us, his students, his opinions on different matters relating to the subject of psychology (which was the class subject), and me just reveling in his various thoughts. I realized after some time why I thought he was such a genius: because I agreed with his philosophies! He thought like I did, and therefore he was awesome! And he still is, on the condition that his viewpoints are still in harmony with mine 😉
Another similarity that furthered this effect was in attitude. I liked the way he looked at things, again only to realize that it’s because I have a similar attitude in regard to the topics at hand. Also humor was a big similarity. He liked to laugh about things. In fact, he wasn’t hesitant to makes jokes about most things. I have the same jovial outlook.
The point is that the likeness he and I shared in philosophy, opinion, humor, and attitude led me to unavoidably like the guy. This is not to mention our similarities in other matters of conduct which still furthered my liking of him. Our likeness led to my liking him. And I assume that given the opportunity to get to know me on a personal level, he would probably like me just as well.