You've all seen the mugs, tee shirts, etc. with the writer threatening to 'put you in my book'. Yes, it's funny, but I would never do it. Some authors do base their characters on real people, but for me it's an an invasion of privacy. And I'd be afraid that the victim might recognise themselves and come round and punch me on the nose!
Which is not to say that I am not an inveterate eavesdropper. Public transport is a great place for this, but anywhere that people gather can be a prime source. What do I get from it? Apart from fascinating snippets that I could/would never use? Rhythm, pace, the pattern of speech and the flow of conversation, which all help with making dialogue sound real.
One of my favourite playwrights is Harold Pinter, who was the master of using a pause - which is something I do - listening to conversation gives the patterns that can be adapted for the book. The way conversations overlap, repetition - although you have to be careful with that or your editor will be putting a red line through it, Local colour and frequently used expressions - swearing too perhaps. Ums and Ahs - we are all guilty of those - make speech realistic, judiciously used.
And then again, despite what I said above, there are occasionally snippets that no one would recognise as theirs. This post was inspired by one I heard last week. Two colleagues in the Premier Inn as everyone trooped back into the building.
'And where were you when the fire alarm went off?
It seemed to me that it would make an intriguing first line for a story.
Maybe I'll use it one day.
And no one will ever know where it came from, will they?