Your source material is the people you know, not those you don't know, but every character is an extension of the author's own personality.
You gotta have swine to show you where the truffles are.
I'm not suggesting that the play is without fault; all of my plays are imperfect, I'm rather happy to say-it leaves me something to do.
Old people whimper, and cry, and belch, and make great hollow rumbling sounds at table; old people wake up in the middle of the night screaming, and find out they haven't even been asleep; and when old people are asleep, they try to wake up, and they can't... not for the longest time.
I am convinced that no one is fully educated without a full grounding in the arts.
Good writers define reality; bad ones merely restate it. A good writer turns fact into truth; a bad writer will, more often than not, accomplish the opposite.