1. What does it mean?
Short for 사람 바이 사람, a playful mix of Korean 사람 ('person') and English 'by.' It says that preferences, reactions, or experiences vary from one person to another rather than following a single rule.
2. The nuance
Useful when someone generalizes about what everyone enjoys or finds easy. It is a casual qualification, not a detailed explanation of why people differ or an excuse to disregard another person's experience.
3. Examples
“아침 운동이 좋은지는 사바사인 것 같아.”
Whether morning workouts suit you seems to depend on the person.
“나는 그 영화 좋았는데 취향은 사바사지.”
I liked that movie, but everyone has different tastes.
Sources
National Institute of Korean Language
References support the meaning and usage. Example sentences are written for NoCapWiki.