At our wedding, my MIL put glitter confetti all over our honeymoon luggage. She even opened up our packed bags to dump in glitter. It was strewn all over the trunk- multiple bags of the shredded foil flat glitter of all sizes.
She knew we were leaving the wedding to drive 2 hrs so we could take an early flight out the next morning. I was livid. It was one of the first times the passive agressiveness was blatant enough for me to pick up on it. Of course, when confronted next time we saw them, she played the "oh, it was just for fun. I had no idea it would be any trouble!"
Today, as I unpacked our bags from our 12-year anniversary trip, I am still finding that damn glitter!
Our relationship is much improved today, with some hefty boundaries and ELC. No unicorns to go with the glitter. 
