For example, you send an unsubscribe message to a legitimate company or a spam, they reply that they will remove you and it may take up to 72 hours to take effect. I find it hard to believe anything that simple could take more than 3/4 of a second to take effect system wide.
Another example would be when you call the visa activation line, there is a "delay" of several minutes while they try to sell you some kind of insurance. Usually just as you get the point across that you don't want it they will tell you your card has been activated and let you go.
Are these delays real?