Movies
Have I stepped over some line in the sands of coolness with you, because excuse me if somebody doesn't know the secret handshake with you.
— Michael · Reality Bites

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker complains about being judged by an unspoken standard of coolness. A boundary in the sand and a secret handshake turn social acceptance into an exclusive club. The sarcastic apology challenges the other person's rules while revealing the frustration of feeling shut out.
Context reviewed