故腻瘾
[gù nì yĭn]
This is a unique mix which translates literally as 'old sweetness addiction.' But it can imply having an indulgence towards nostalgic things. People might use this to express they are deeply addicted to something from their past, whether good old habits, people or experiences which always bring warmth and comfort. Alternatively, someone may enjoy reminiscing over past pleasures as a guilty yet sweet habit.