9. Too much arguing
On a positive note, arguments are a part of every human relationship. The process of understanding each other sometimes lead to minor frictions but those frictions never wear out the strength of the union. But if arguments continue to happen and the two are not able to find common grounds over things that differentiate them then it may prove unhealthy for the relationship. Marriage is not about ensuring same opinion or outlook on everything; it is more about agreeing to disagree where opinions differ.