Should I base characters on people I know?

Should I base characters on people I know?

Russell Celyn Jones (Published writer. Professor of Creative Writing and Director of the MA Programme at Birkbeck College (University of London).) gives expert video advice on: How do I build a character?; Do some characters write themselves?; How can I make a character believable? and more...

Basing characters on people is tricky, because you're usually too timid about making those characters do terrible things. Sometimes you have to base characters on people you know, but those characters in your fiction will change and will alter to such an extent that by the end of it they probably will not resemble the people they were originally formed upon.