You can easily create new qualities for your world. It’s just a few clicks. But should you? Often, you shouldn’t. The best of all worlds is to keep the number of qualities low, and get a lot from each of them. That way both you and your players have an easier time of keeping track of things.
Sometimes you can only use a quality for one thing. If your quality controls progress along a particular story, you can’t much use it for other things. But you might have a quality that increases when you fail at various challenges across your whole world (like Nightmares in Fallen London) or a resource that can be picked up in many places and spent in just as many. Or a quality that recognises when the character has been thoughtful or ruthless. A small number of qualities can go a long way. Failing to be parsimonious with your qualities can lead to Combinatorial Explosion.