When you have a habit that is clearly bad for your health, but it gives so much happiness...pure joy and bliss, that you just stick with it anyway.
After a life of struggling through sleepless nights, Jane discovered cognac. Now when she wakes in the night, sipping some cognac makes her tickle, giggle, then fall back into a blissful sleep. She know it's unhealthy in the long term, but it's pure joy every single night. She's willing to accept death by bliss.