That makes no sense at all. Unless we are just looking for joke answers here.
My best quality is probably my ability to adapt to almost any situation and eventually thrive in it. I can handle pretty much anything that comes at me and at least seem like I know exactly what I'm doing. I think that's been my best quality for most of my life.
My worst quality is tough because I think it's changed a lot over time. Apathy and lack of ambition used to be in there but I don't think I have that as much as I used to. Maybe now it is my commitment to routine and stubbornness to break from the routine.