With 7 billion people in the world, there are two facts it takes very little research to know they are true. One is that someone out there is going to be so compatible with you it'll be like you were somehow separated at birth. The other is that someone out there is going to be so incompatible with you that it's impressive you two ever thought you could have belonged together in the first place. All things being equal, you're probably going to meet both of these people and have a relationship with them at some point in time. 

Eventually, we all figure out who's compatible with us, but it's that "eventually" that gets you. That can be a long time. Too long, sometimes. And sure, any relationship requires work, and you need to put the effort in to make sure it runs smoothly because nothing starts perfectly and runs that way all on its own. But who said you were asking for perfection? We're just talking compatible here, which is a much more achievable goal. If you're not sure just how compatible you are right now, why not answer a few compatibility questions and see where you fall on the scale?