The elusive ‘Compatibility’ with partner

So often in our day to day life, we come across people talking about the compatibility between life partners. These are people cutting across religions, nationalities, genders, and age groups, but talking about the same elusive ‘Compatibility’ in their married lives. People from all sorts of relationship backgrounds like living-ins, looking to get married, married, long-married and so on are either hopeful of compatibility or are perturbed for not yet having the compatibility. At times I feel, is Compatibility a milestone to achieve, which once achieved will never ever wane off? Perhaps not. If so, is this chase and such a big noise about compatibility worthwhile? Or, people are just using this word to hide their own limitations.