The stable strategy is the one where no player can change the strategy and expect the new equillibrium to make them better off.
If an office has break room with a ten cup coffee machine and the person who drinks the last cup of coffee has to make another pot, then here the expected reasoning of the coffee drinkers:
Low ranking staff take cups 1-9. Supevisors take cup 10 because they won’t use their valuable billing hours making coffee. Low ranking staff that see there is only one cup left will wait an hour for the supervisor to make a cup of coffee. Fortunately there is an office manager, and coffee reappears.
I guess the optimal strategy is to observe that there isn’t any punishment for not refilling the coffee, except the risk that no one else will refill the coffee pot that day. Eventually the equillibrium would be met where the cost of refilling the coffee pot equals the cost of not getting a 2nd cup of coffee later that day. Each period people move back and for between being the sort of person that re-fills coffee pots and shirks until there is nothing additional be gained by switching to shirking (e.g. additional coffee w/o work) or switching to beign a refiller (e.g. additional coffee, albeit sometimes with work)