wow some truly awful PIL here!! really feel for anyone coping with some of this awfulness
I'll add some hopefully more light hearted ones..
every time I have ever been to stay with MIL she has only ever put one towel out, for DH. I always always have to ask for more. There are now four of us and this still happens.
For a long time she only had photos up of me with my eyes shut in them. including a wedding photo (that she had taken, badly).
She also positions greetings cards on her mantelpiece so that they cover me in photos 
When staying with her she wanders in and out of our room 'helping' by flapping bed covers etc 
She once tried to correct me saying I had got DD's birth month wrong
I hadn't.
She doesn't approve of tipping and once after a group meal out I caught her taking money back from the tip!
When we were buying our first house and stressing waiting to see if the offer had been accepted she said 'I don't know what you're worried about, it's not your money'. most of the deposit was DH's due to an inheritance but even so..
She and FIL invited themselves to stay with us on our first valentines day living together, and then followed up the next year by inviting themselves for our first wedding anniversary. We told them they were welcome to stay and promptly booked a weekend away. They thought it would be 'nice to celebrate together'
Thankfully she has mellowed over the years but I definitely have a threshold amount of time I can spend with her!