Narcissists are great mimics.And why did Steph make the sign of the cross before entering the chapel, considering she says she is non- religious or an atheist.
By making the Sign Of The Cross, she's trying to show that she identifies with Chateau de la Motte's owner (I own a chateau too. It also have a chapel). Hence the copycat behaviour. In these circumstances she will always interject with something along the lines of that 'It's giving me great ideas for laLande'. Ideas that never come to fruition. In trying to identify with a different chateau owner she is, in effect, saying 'I am your social equal'. When the reality is that she's not even in the same stratosphere.
She's just on planet Stephame-me-me - a gas giant about to be sucked into a black hole.