I used to work with one smug idiot who would keep a track of when people arrived - she dropped her kids off at 8.15 so was normally at work for 8.30 for a 9am start.
She didn’t do anything in those 30 mins - she got a coffee and breakfast, she wasn’t being paid so fair enough.
Oh, I had one of these. Always mentioning at every opportunity that I came in 'late' (with the clear implication of me being cheeky), but I did 9-5 whereas she did 8-4 every day. The management stipulated that the department would be ideally covered from 8 o'clock if possible, but that 9-5 were the essential core hours.
We were a very small team and she couldn't countenance the very thought of having to leave a minute after 4:00 (always left on the dot or a bit earlier), so 8-4 greatly suited her. She either didn't realise or care that, had I not been willing to do 9-5 (which suited me better) and wanted to do 8-4, she would have had to work until 5 two or three days every week. Something about gift horses and mouths, I think.
Anyway, she made a massive show about her 'being the early shift, getting half the work done before I arrived, she was obviously the dedicated worker being 'willing' to be there for 8am, somebody had to be in early' (they didn't - it was her preference) when I (and most of the rest of the office arrived at 9 or just before.
On a few occasions, when we had a big backlog, I came in early myself, to do 8-5. It became very evident that, every day, she got there at 8am, logged on and sent one email from the department inbox (usually forwarding something with 'FYI' - 5 seconds' work); THEN, she would spend the next 50 minutes chatting, phoning her friends who worked there on other floors (not even a pretence that it was work-related), getting toast from the canteen and taking her time over eating it, same with coffee, more chatting, discussing her plans for the evening - then, as people were starting to arrive from 8:50, she finally started working normally.