Physics of Motors question please help?

So here's the thing, almost all motors are made by winding many turns of wire around pieces of iron, arranged so that some of the pieces of iron can turn inside the other pieces. What I do know is that motors generally rotate something so it should I would say it's not surprisng the electric motors work on the principle of one magnetic dipole causing another to rotate. But here's what confuses me. Why aren't motors made of simple coils of wire? Thanks for your help.