Does it matter which direction the spring and damper forces point?
In one of the examples in my professor's lecture, he stated that if we define y to be positive when pointing up (see image below), then the damping and spring forces must be in the opposite direction. He went on with another example where he redefined the positive y axis to point downwards, and this resulted in the damping and spring forces to point upwards. Note: the gravitation force is missing in this picture.
I always thought that direction did not matter, am I right?