I have never worked on any large project. I just unsubscribed from one of the old newsletters I've been getting and the message stated: "Your cancellation may take up to 7 days to implement".
I've always wondered why are some systems made this way that it takes them so much time to implement such a simple change. Is this due to having multiple servers and application spread all over them? Or such a heavy load that deleting the record gets very low priority? Or maybe just clumsy architecture?