Sometimes nipples are too big. An infant may seem to gag and choke if the nipple is so long that it goes past the hard palate and touches the soft palate. Your baby may react by fighting. When put to the breast he may turn his head, cry, and move his arms and legs. This can easily be corrected by holding the infant a little away from the breast.
A similar effect is produced when a mother has too much milk and it flows too fast out of the breast due to a forceful ejection reflex. The milk fills the infants mouth too quickly, and chokes him. In this case, the mother should express some milk before she feeds the infant.
All these are reasons why a baby may seem to refuse the breast, and yet in most cases the mother has more than enough milk, and keeps wondering why the child is refusing feed.