Why this thing happen when I add screw modifier?

Hi, can someone explain why this thing happen? I use NVIDIA GeForce 210 64bits 1GB DDR3. I’m a newbie, thanks for your help.

it won’t work on a plane. it has to have a Y value, and a plane has only X and Z values.
(edit) also, it won’t work if the cursor is centered, and a single row of edges is best for a screw, whereas a circle will make a spring.
(edit) actually the spring invloves an extra step, which i can demonstrate if you wish.