A duvet day is about as basic as it comes, but it feels surprisingly indulgent. It feels like you've pulled a sickie from school and you've got away with it. Stay in your pyjamas all day. Lounge around. Watch trashy TV. Eat what you want. You don't even need to have a wash if you don't fancy it. Yep, you'll feel like you're bunking off life for the day — and you'll love it.