The WORST response to a "Yes" or "No" question.
The response you give when you don't 100% want to say "Yes" but also
don't want to say "No". "Sure" is the answer you use when
on the fence about something, but is not an acceptable response to Y/N
questions.
Phil: Do you want to go to
the movies?
Sarah: Sure
Phil: (pause) Is that a "Yes" or "No"?
Sarah: Sure, I will go to
the movies.
Phil: But I asked if you WANTED to go to
the movies.
Sarah: And I said sure.
Phil: (leaves)