On the other hand, " Knock yourself out, " like " Have a ball, " " Be my guest " and " Go crazy, " is a sardonic way of giving permission, when your permission is solicited, to do something in which you have no intention to assist or participate.
On the other hand, " Knock yourself out, " like " Have a ball, " " go for it " and " Go crazy, " is a sardonic way of giving permission, when your permission is solicited, to do something in which you have no intention to assist or participate.