Should you require something back from the user, Tkinter has four more message boxes for you:
askquestion will allow any question to be passed in and provides Yes and No answers. These are returned to the program as the string literals "yes" and "no".
askyesno does the same, but will return 1 on Yes and nothing on No.
askokcancel provides OK and Cancel buttons to the user. OK returns 1 and Cancel nothing.
askretrycancel provides Retry and Cancel buttons. Retry returns 1 and Cancel nothing.
Despite the seemingly large number of choices, these all do pretty much the same thing. There doesn't seem to be much of a use case for askquestion over askyesno since they ...