Yes, I was writing one yesterday, because I was submitting a new play to a group that performs readings. I have a tendency to resist, to want to say, the play takes 87 pages, with no wasted words, to state itself, I can't boil it down to a paragraph or two! But of course I can.
I suppose if I worked according to a formal outline more, I might have a pre digested summary ready at this point. But I work from a vague sketchy outline, and then when I'm done I step back and ask: how would I summarize this?
I'd feel belatedly dumb
If I couldn't find a sum.