For me (only speaking for myself), the connection comes from shared interests to an extent. But for me that's no where near enough to putting together the whole puzzle - my interest is there or it isn't, for lack of a better way to explain it. I know a girl (who has a boyfriend) who shares almost everything in common with me. Loves the same games, same music, same books, razor sharp (like top of our grad school class sharp). She's cute. But I see her as a great platonic friend. I think she's interested in me because the other night she got touchy-feely after drinking and we frequently text. Meanwhile, the girl I've fallen for (who has a boyfriend) does share baseline interests with me - same program, certain temperament. But as people we're actually fairly different. What attracts me to her isn't really describable, it just is, and THAT type of attraction (for me) is exceedingly rare. So my point with Tinder, etc. isn't that "it doesn't work" - it does for tons of people. I have a friend who met his fiance through it. But it's not right for me. I can't turn on an app and seek that flame - I need to be in proximity to girls, naturally, and let things go from there. That's just me. And that's what makes this shit so hard, because I know that puts me at a disadvantage of finding a relationship.