Maybe some members/guests do not yet know about this kind of sentence.
Mona: Why are you so sad today?
Raul: My girlfriend is angry with me.
Mona: What did you do?
Raul: ALL I DID was say she was getting a little too fat.
“All I did” = The only thing that I did.
Some native speakers add two words: “All THAT I did was TO say she was getting too fat.”
But many native speakers feel that the sentence sounds more natural WITHOUT those two words.
I have made up two more examples.
All I did was arrive one minute late. (But now the boss wants to fire me!)
All I did was say “Good morning.” (But now Patricia thinks that I love her!)