Why do mother-in-laws think we will treat them like we treat our own mothers?

Don't they realize that is impossible and that for a lot of us, those feelings aren't there and that we have our own mothers and that we simply don't want to treat them like that? They are our mother-in-laws, not out mothers! Big difference! I don't get it. My FMIL told my FH that I should be treating her EXACTLY like I treat my mom-to her that means I should go shopping and on lunch dates with her, mani pedis and that I should greet her with a hug and kiss. Um, no. I give FMIL a handshake when I see her and I have no interest in all those activities with her. She has daughters to do that with. She is very presumptous for even thinking I would consider her the same as my own mom or have those same feelings for her. I don't expect her to feel towards me as she would feel toward her daughters.