I work till 4 in an office where most people work 9 till 5 and quite often get the 'see you Part timer' comment when I leave.
They forget/don't know that invariably I am in at 7.30 (7.45 latest) whereas they roll in through the door bang on 9 and spend the next 15 minutes getting themselves a coffee, switching on their computer, selecting which pen to use for that day and asking everyone how their evening was!
This brings back memories. I used to work in an office that was flexitime. I used to do 7-3 so I could get out the door early to really enjoy the rest of the day, loads of people used to give the 'part-timer' comments as I left. I had to remind them every day that their 9-5 was EXACTLY the same and that they must be thick as PIGSH!T to not understand this.
I think I made a point of saying 'couldn't get out of bed this morning, I've been here 2 hours already' at 9am everyday just to annoy them,