(idiom) the rest of your life.
I will be with you for the rest of your days (Divorced after three years)
6π 1π
When your cordially invited to go Fuck yourself!
History: When in the Hell did we start inserting βrest of yourβ in the salutation, βHave a nice (rest of your) day!β
I.E. When you leave a small tip, or in current times, when you frequent almost any establishment, and upon exiting the premises an employee will say, βHave a nice REST of your day!β