I was about 13 years old and flying on standby as a member of UA's 12-21 Club. Young people between the ages of 12 and 21 could fly standby on a reduced fare. The gate agent kept me aside until everyone had boarded and then gave me a boarding pass for what she said was the last remaining seat. She had a big smile on her face. I thought she was just being friendly.

I ended up turning left when I boarded and was seated in F. Holy cow. I remember trying to not be too obvious about watching the other F passengers, trying to determine appropriate behavior. But I'm sure I stuck out like a sore thumb.