You don't make it harder YW! It's just babies and their parents. To be honest, it's babies and their mums! Nothing to do with experience!
I have seen both my children do exactly the same things - play up for me.
I know O whinges about 50% more when I am there. I know this because I am listening from upstairs
.
I can safely leave DS1 with O while I go off and get ready upstairs. Yet he gets in to all kinds of shit, cries, whines, and attaches himself to me the second I am in the room.
He thinks I am a fool! I am not! I know he just does it for (more!) attention! He wants me, and all my attention if he can see me!
At work, I am a dab hand in getting the newborns to settle. Getting them to feed (usually!) etc. Mums look at me with amazement at this 'ability'. It's not ability, it is just easier as an outsider to deal with the babies needs in a less emotional manner. And they can't smell their mum. Just me, which in a hot maternity ward, I'd rather go the fuck to sleep than smell me!
Yet it was hard with my own... funny that
.
And that is why J was fine for your sister
.