Much of what is valuable in this world is the product of mashing up ideas or music or personalities that are on the face of it incompatible. And the secret is that great chemistry (for example in music) isn't about putting together people who are on the same page—it is about putting together people who are different and making it work. The result is often unexpected and beautiful. So it is with relationships; compatibility is a terrible idea in selecting a partner. It leads to stasis, both for individuals and for relationships and (turning my music example into a metaphor) it leads to music that is predictable and unexciting.