One person in nearly every workshop asks me what two Colors are the most compatible for a good relationship. My first answer is that it's difficult to maintain a powerful relationship when there are no shared values in the first two Colors of your spectrum. For example, a Blue-Orange person may struggle to stay on fire with a Gold-Green person.
Let's clarify that: The Blue-Orange person will HIGHLY value intimate closeness, plenty of sharing, a mountain of kindness, spontaneous fun, plenty of options, and artistic endeavors. The Gold-Green person will likely find the Blue-Orange values less important than a highly planned life, adherence to traditions, a continuously balanced checkbook, orderliness, plenty of alone time for intellectual activities, and more informative and engaging coversations than a lot of small talk.
And if one is an introvert, the other an extravert -- well, you can predict further possible barriers to high energy and excitement in the relationship.
Don't get me wrong. Opposites do attract, and quite often opposites enjoy each other's company intensely. In a phrase, they "complete each other." However, my experience with hundreds of clients is that, although all couples need to work at building their relationship every day, the "opposite" folks often have to work harder to make it work out -- and sometimes that's TOO hard.
Do people who are "alike" turn out better? Sometimes, but not necessarily. Experts, e.g., keirsey.com, say that people of similar temperaments may end up competing for the higher ground in values, can share common weaknesses and, as parents, may model the their same worst traits for the children. One thing for sure, what a person dislikes about himself he may dislike even more in the mate.
So what Colors are the most compatible? The simple answer, in my opinion, is that one should first look for a sizeable number of shared values. The vital and innate things that we share make it earier to relate, to bond, and to support joy over all possible conflicts.