It comes down to alignment of interests and alignment of values. I think previous comment is right in suggesting that people's interests and values may not be c

It comes down to alignment of interests and alignment of values. I think previous comment is right in suggesting that people's interests and values may not be clear at that level. People often hide them to appeal more broadly. The more you reveal about yourself, the fewer people you will appeal to because very few people share your exact values. People tend to like people who share some obvious common values and they assume that the values that are unspoken are also a match. In reality, it's rarely so. As people learn more about the world and themselves, they begin to realize that some values that they didn't consider before are very important and they may be shocked to find that certain people they used to like do not share those values which they took for granted.