IMO, ALL couples are sub/Dom to a certain extent. It may not be enough to show up on the BDSM scale (i.e. one of them always defers to the other in a very obvious way) but if you watch any couple you will see a power exchange dynamic between them. I think arguments are more likely to occur when two people are very similar - two Doms and two subs (or two vanilla people who are equally dominant or submissive) would be a total nightmare in a relationship because they will argue. However, with a Dom/sub combination you are more likely to reach that compromise level where arguments are rare. Mainly because the sub will give way more and allow the Dom to have their way.

But, having said that, even a sub's supreme tolerance for the crap Dom/mes throw at them is limited so eventually they will break. And a Dom/me famous patience can also crack when a sub is particularly annoying at them. Arguments happen in any relationship. A good relationship is one where you manage to find a comfortable level of compromise that suits both and therefore limits the arguments.