A few times I have seen a certain shoe highlighted, then click on it, and it is Not Available but here, people who bought these also bought these: and then you click on those and every color, in every size is Not Available, but here, try these over here etc etc. Aaaagh! Another time, I got clicked something into my cart only to get a message Sorry, this is not available, But when I went to start from scratch, there is was again! It got into the cart, but when I went back, nope. Not available! How does this not happen automatically, that something only disappears once the last one is purchased and that purchase finalized. Other sites seem to do it just fine.