Step 1: Select a palette that screams "I've given up on life, but I'm still trying to look cool about it."
Step 2: Add some comfy, yet slightly disturbing, IKEA furniture to make your bunker a home away from home.
Don't forget to include a few 'emotional support' items, like a faded 'I'm With Stupid' t-shirt and a worn-out 'World's Okayest Bunker Dwellers' mug.