Edit: I also think the process of being drawn to someone does not have to be entirely unconscious. You notice something they did you admire, and so then you notice a skill. The first impression doesn't have to have a significant emotional impact. It can be a series of information that eventually forms a complete picture of someone you respect or who you think will understand you or reciprocate intimacy. It doesn't have to be mysterious or intensely emotional until a series of decisions eventually define it as love.