My MIL is lovely. She's kind, funny, loves dc, spoils them rotten and has been very supportive to me over the years.
I think my favourite tip of hers was not to do the cleaning, washing up when the dc were napping. No, put your feet up she said. And do that while they're awake.
DH on the other hand, has a dreadful MIL. I'm very lucky he's a tolerant man.