This thread has taken a strange turn.
klog I will google that information, it sounds very interesting, thank you. You made me smile, I've changed brands 
ZeVite thank you for the flowers. 
OP I think you are right, there are some bad MILs, some bad DILs, some bad DILs who go on to become bad MILs, and some perfectly lovely people who just need a bit of time to get to know each other and learn a bit of give and take.
I'm not sure what you really wanted from this thread other than that, but yes it's certainly not true that all DILs are lovely and all MILs are not. I know my MIL would never have allowed her MIL to behave towards her the way she seems to think she can to us (her DILs, and yes, to her actual children as well).
It's all gone a bit food focused since I last posted. So aside from really wanting a portion of lemon chicken right now, there are a few possible things that could have happened with the takeaway.
Your DS thought about it and asked to change takeaways of his own accord.
DIL asked him to ask if you could change as she didn't fancy the same thing again so soon.
Your DS asked you to change and you changed it.
Your DS asked you to change and you said no.
Your DS asked you to change and you said okay but your DH still ordered from the chinese takeaway (we do this all the time when we can't agree which we want).
You all ordered pizza or kebabs instead.
I mean, if you think she's princessy, you should see us when we order indian takeaway but I will only have the one thing particular thing from the one shop because the other shop makes it too spicy and don't put a tomato on it, but then I need to get skinny chips from the kebab takeaway shop to go with it because they only do chunky chips at the indian takeaway and I don't like them and I don't like their rice (it's pointy and harder than chinese takeaway rice, but you can't have chinese takeaway rice with indian takeaway food) but I do get a garlic naan and no I won't share it, get your own. I'm like that entire episode of Gavin and Stacy all on my own when takeaway is concerned.
There's a surprising number of people still prepared to eat with me 