While the initial feelings may (or may not) come from lust, what happens next -- if the relationship is to progress -- is attraction. When attraction, or romantic passion, comes into play, we often lose our ability to think rationally -- at least when it comes to the object of our attraction. The old saying "love is blind" is really accurate in this stage. We are often oblivious to any flaws our partner might have. We idealize them and can't get them off our minds. This overwhelming preoccupation and drive is part of our biology. We'll go deeper into the chemicals involved in attraction in The Chemistry of Love.