Shared Elements are what attract us to others, but shared qualities have a friction and tension that make animosity a likely outcome. If you are in a relationship with someone whose zodiac sign carries the same quality as yours, you might share some similar attributes that actually upset you. The tension between signs of the same quality is a natural manifestation of seeing what we don't like about ourselves embodied in someone else.
Cardinal Sign Tension
If you were born under a Cardinal sign, you might notice that others who share this sign's quality will challenge your originality and question the premise of why you are doing what you are doing.
Fixed Sign Tension
Two Fixed signs will inevitably butt heads over protocol, regulations and other ways of doing things that might be open to interpretation. The danger is when one Fixed sign lets the other feel too in control and applies late pressure to release or share that control. Tension flares indeed.
Mutable Sign Tension
Two people born under mutable signs may work at cross-purposes so independently of each other that they will not realize how sabotaged their efforts are until they see the progress each other has made. There must be a cosmic reason the letter M starts off both the words Mutable and Mess.