Whilst the form of the cup is important, so's the bottom.
You'll notice potters tend to pick up pots and look at their bottoms.
A bottom tells you a lot. It tells you about how a potter handles clay and can give you an insight into their character.
Once upon a time my bottoms were very controlled. I turned feet on all my pots. They were very neat and precise.
But I've relaxed a lot since then and discovered that a loose, straight from the wheel bottom can be just as effective.
You can see in the picture the marks from the cutting wire. Once the pot is leather dry I then also "roll" the bottom of the pot on the bench to smooth down the sides from where it's been trimed and to soften the form, tucking it under.
Then it gets it's stamp, so you know it's one of mine!