While some people may first consider the implications of a "reproductive-potential" partner (i.e., I want my children to be tall, good looking, and smart), few people consciously choose partners based on either of these (opposites-attract, reproductive-potential, pattern-recognition) qualifiers... though the last one, pattern-recognition, might be closest to the truth.
If we look to eHarmony, we might be inclined to believe that most people choose partners based on a similar self-knowledge - a similarly held awareness of ones beliefs, desires, and sensations. While this is significant, it is not always account for the many common dynamics we encounter in relationships (why do people break-up, what's the deal with love/hate relationships, and/or why do some relationships start out intensely only to fizzle-out quickly?).
Researchers who study attachment often times look at six primary elements of attraction:
IN OTHER WORDS
While researchers and people around the world tend to focus on the first six (attractiveness, financial independence, common interests, religious beliefs, social standing, educational attainment) elements, it may actually be the nature of our physical structures and their natural reactions to one another that determine how we "fit" together electrically and magnetically (i.e., compatibility).
Electric charges of the same type ("like charges") repel
Charges of different types ("opposite charges") attract
Charge is a single conserved quantity or stored energie ("waiting for the right person to come along"). Depending on the person who comes along, this stored energie can react in two distinct ways (repel, attract).
What happens when people who "wouldn't necessarily go together" get together and actually end up interacting in a harmonious state?
All objects (human beings, included) have different chemical affinities for electrons. One entity (surface) can steal electrons from another surface ("drain another person of their electrons"). Physical closeness leads to charge transfer due to contact between two distinct surfaces causing them to "mesh well" despite their initial differences.
IN OTHER WORDS
What attracts or repels us from someone is related to the inherent difficulty in maintaining a constant charge between two objects over distance (i.e., "out of sight, out of mind").
We've all seen this effect. One person hangs all over another person, while the person being clung to usually reacts with annoyance. What is happening here is that when a negatively charged object (person in a "bad" place) gets near "the relationship zone" (i.e., the wall), the relationship's (wall's) positive charges shift toward the other person causing one person to cling (similar to how positive charges shift toward a sock).
Then, the other person's natural defenses (i.e., wall) cause them to shift away from the object (i.e., clingy person). The result is a a relationship (wall) that becomes electrically polarized.
These types of relationships are those that are often times referred to a "love/hate" relationship whereby opposite charges are heightened (hate) despite attraction continuing to dominate (love).
Charge has electrostatic potential energie (EPE). Voltage measures the EPE per unit of charge. Working on a relationship like this (counseling) can result in either raising the voltage of positive charges or lower the voltage of negative charges.
Charge can escape through electric conductors. Insulators (safeguards we put in place to protect our relationships) have no mobile electric charges. This means that the safeguards we put in place do not follow the relationship wherever it leads. This is why it is important to continually renew one's relationship (i.e., continue adding insulators) in order to protect its charge.
Conductors (beliefs, morals, relationship goals) do have mobile electric charges. Conductors allow charges to cancel or escape. This is the effect known as supporting each other's growth.