1. What does it mean?
복세편살 abbreviates 복잡한 세상 편하게 살자. It is a casual motto about reducing needless stress, not overcomplicating small decisions, and choosing a more comfortable way through everyday life.
Also written or said as boksepyeonsal
2. The nuance
It can be comforting or humorous. It does not have to mean abandoning responsibilities, and it may feel dismissive if offered to someone facing a serious problem.
3. Examples
“작은 실수는 넘기자, 복세편살이야.”
Let's let the little mistake go; life is complicated enough.
“복세편살하려고 아침 준비를 전날에 해 둬.”
To make life easier, I prepare for the morning the night before.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.