when my son was about 2 i would remind him “to behave”; one day he had had enough and shouted, “I’m not being have!”
my husband is a cohen. the first time he took our sons to duchen with him, they were about 5 and 4. The 5 yr old, a sensitive soul, came home in tears: “It was so embarrassing! They took away Tatty’s shoes and he had to stand up in front of the whole shul and they all said ‘Oy, yoy, yoy, oy yoy yoy’ to him!” he really didn’t want to ever go through that again.
our 3.5 yr old daughter was cutting up some paper and making a mess. i asked, wouldn’t you like to be a mitzva girl and clean that up? she said, no, i want to be a teshuva girl and keep doing this till i’m done.