My biggest issue with the checkout process it that once it is in your cart, you should be able to proceed without being told in the next step that your cart is empty. If you received a message that said the system is busy, etc. and you needed to refresh, that would also be ok. But, when it tells you your cart is empty and you have to start all over, that changes everything because people who started the process after you, now have a chance to get the item since you are spending your time starting all over. If you were there first, you should have some type of place holder.