This happened last year or so.

1 morning, during the weekdays, i head out to get to work using a public transport (aka monorail then bus). I haven't even fully awake yet and was blur during that time. Got into the monorail and it was slightly packed. So i stood in front of this lady and listening to my headphones with bliss. When i reached to the station, i got off and this guy tapped me on my shoulder and told me that i didn't zip up my pants.

He could see my zipper popping out from my pants. I facepalm.