I'm not a geomtry-cist (I made up the word, indeed I did, blame the head cold)While my Celtic background leans me towards lovely curving lines, I have to admit angles come in handy. Nor is one type of angle better than another. Cylinders, squares, rectangles and triangle are all equally important. Can you imagine a turret made like a square? It would be a courtyard.
Triangles though are often used as plot devices and they make me crazy. It's my own personal belief system that if you haven't chosen one lover over the other by book nineteen, you are not the type of person with whom I wish to spend time. That's selfish, and cruel, behaviour. At some point in time, your feelings towards one person are stronger than they are for the other person. Rarely do all three form a perfect equilateral triangle. As a plot device, they are the more common, and cliched, scalene triangle which has no equal sides. It's unbalanced from the beginning. Walk away.
What plot devices most annoy you?