I think Japanese use ~くれる and stuff also when someone does something for someone else even if that someone else doesn’t appreciate it. It emphasises that the deed has an impact on someone else. But that’s just my understanding.
とんでもないことをしてくれました = he did something outrageous that effected me.
とんでもないことをしました = he did something outrageous (and I was just witnessing it).