"I'm afraid you'll say something or do something that you'll be sorry for afterwards" Sheila warning Mrs Birling that the Inspector knows more than she thinks Act 2, understanding Inspector's role in the story.
"We really must stop these silly pretences" Sheila Act 2, trying to be assertive but is failing
"You and I aren't the same people who sat down to dinner here." Sheila Act 2, showing emotional maturity
"You don't seem to have learnt anything" Sheila to parents Act 3
"Everything we said had happened really happened, If it didn't end tragically, then that's lucky for us. But it might have been done." Sheila Act 3, emotional maturity and intelligence develops, accepts blame and responsibility
Priestley uses Sheila to show growing socialism in a capitalist society, rising importance of women and hope for future generations