I had a dream that my parents were arguing…
To dream of your parents generally represents authority, comfort and affection- as these are usually the feelings that come to mind when we think of family. However if they were arguing- it may be that you are projecting your own anxieties and worries about them and their relationship into your dreamscape.
Perhaps the thing they were arguing about is something they argue about regularly and you worry it drives a wedge between them now. Maybe you foresee the thing they were arguing about as something that will cause them bigger problems in the future.
If you dream about friction within the family, then it is likely that conflicts in your waking life will occur. Perhaps your predictions are correct and you can feel the tensions rising when you are around your parents. You might know from past experience that an argument will likely be a result of these differences of opinion.
To see two parents arguing might encourage you to look more closely at a relationship involving a third person as you were the onlooker to their issues.
It also acts as a reminder that these two people have their own set of needs and yearnings and you need to appreciate them for who they are more, rather than resisting aspects of them you perhaps don't agree with.