Digging Up Bones
The idiom "Digging Up Bones" refers to someone dwelling on a long-past relationship which he/she regrets losing.
Breaking up with a significant other and thinking about all the good times you shared together on Valentines Day or their Birthday etc. would be considered "Digging Up Bones."
Digging up Bones
When you are constantly running into elderly people. Being the youngest person at any given space by at least 40 years.
I went to Java City the other day, and between the customers and the barista, I was digging up bones.