Mistakes were made
"Mistakes were made" is an expression that is commonly used as a rhetorical device, whereby a speaker acknowledges that a situation was handled poorly or inappropriately but seeks to evade any direct admission or accusation of responsibility by not specifying the person who made the mistakes, nor any specific act that was a mistake. The acknowledgement of "mistakes" is framed in an abstract sense, with no direct reference to who made the mistakes, or the nature and extent of them.