It means: the wonderful life you have experienced with someone, during which there were some things of great commemorative value. When you see those things, you will think of someone, and when you go to a place you have been before, you will think of the relationship between you.
1. From "Legend Yan Rui" by Pei Kai of the Tang Dynasty. "The imperial concubine gave her a rhinoceros hairpin to avoid dust and said: 'I will miss you when I see things in the future.'"
2. Synonyms. Touching the scene makes you emotional, seeing the scene makes you sad, touching the scene makes you sad, touching the object makes you emotional, and touching the sight makes you sad.