"sorry I have to leave because..." lies

[Jimjam]

I'm cool with people dropping as they please...

That said, if you are baby sitting, on call, have a vigilante super hero persona: just let the group know before you join! It really helps to know who might be leaving at a moment's notice when filling slots.

No one is going to be mad at you because you got an impatient, bitchy wife if you just give fair warning first.