Written by their baby/small child.
Like, “Mummy and Daddy really like the boots you bought me. They’re always making me wear them”
Stop this. Stop. Stop it.
Or if you’re going to do it, go the whole hog. Can’t have the baby supposedly writing it but in perfect adult handwriting. Write it with your left hand/force the baby to attempt to write it. CONTINUITY ERRORS, PEOPLE!.
N.B. Obviously this doesn’t REALLY annoy me, because I’m a total chillbro, just totally chilled, completely chilled out