The superficial relativity of our affections.
When we fall in love or simply we like someone, we are usually attracted to external body parts, too. Face, eye, calf, breast, muscles, hand, nails and so on. Sometimes we look away or don't even start a conversation at a bar, and we cannot imagine we could become a couple with the other person. Sometimes we draw conclusions in terms of health, attractiveness, or merits, based on solely the look and feel.
That's fundamentally real, and at the same time absolutely illogic and unproductive. The organs we are able to scrutinize with the eyes and our hands constitute a very small portion of all of them. What about the other individual’s spine, liver or bones? The brain and the veins?
Sure, it’s not realistic, and it’s foolish to have an X-ray generator and other medical tools with us and continuously examine the others. We cannot fight against the role of the phenotype in a species created via evolution. But we learn a lesson here: how unimportant and irrelevant it can be the set of observable traits of a human being when it comes to forming long lasting relationships. Not to mention the internal values which cannot be seen from the outside at all.