Let's start with the honest part. Aries wants to decide tonight and Cancer needs to feel into it first, and that gap can turn a simple "where should we eat" into a real standoff, because both of you are cardinal signs used to setting the direction rather than following someone else's lead. Aries will suggest the new Thai place, book it, and be halfway out the door while Cancer is still quietly weighing whether they even feel like being around people tonight. That impatience can read as steamrolling, and Cancer's hesitation can read as difficult, when really it is just two different rhythms of initiating a life.
The planets add another layer. Mars wants motion and confrontation, plain speech, a decision made out loud. The Moon wants safety first, an emotional read of the room before anything is said. So when Aries snaps something sharp in an argument, meaning nothing by it, Cancer can carry that sentence around for days, hurt in a way Aries genuinely did not intend.
But here is where it actually works. Cancer is one of the few signs that can meet Aries' boldness without flinching, because underneath the softness is real backbone, the kind that shows up fiercely for people they love. Aries, in turn, gives Cancer permission to act instead of overthink, to just call the landlord or confront the friend who overstepped. Aries becomes fiercely protective of Cancer's tender spots once they understand them, and Cancer becomes the person Aries actually wants to come home to, not just run toward the next thing with. The friction never fully disappears, but the loyalty on both sides is real, and it deepens with patience.