Perhaps it was ingrained in me very early on. First job = RAF and some bugger used to blow a bugle down me lughole at 0530 every morning. First parade of the day was at 0630 for Breakfast and missing that meant (i) you went hungry and (ii) you were absent without leave and got 7 days jankers. If you weren't lined up, fully washed, shaved and in battle dress outside the hut at 0629 you were "late on parade" and that was worth 3 days of pot scrubbing. 20 months of that and you learn to get up and get on. Funny but once I left the training camp I was on shift work and never had to worry about it again. Once out of the RAF getting up to go to work was never a problem. Get there in front of the foreman was always a good motto. As I worked my way up the greasy pole I graduated to retail and there you HAD to be at your work station before the store opened. (Think Grace Bros).
6 years with the Post Office meant more early starts or night shifts and again time keeping was very strict. Not there at the appointed time some b@st@rd had your duty on overtime and you got sent home.
Eventually I learnt how to spell eggsecutif and then I found that I were one and that meant being due in at 9am but in reality being expected to be in by 8 if not 7. It also meant leaving at 5pm but in reality one never left before the MD so more usually 7pm when it was all to the pub for two pints and the crawl up through Archway and thence to the A1M and home at about 9ish. (Usual haunt The Lamb Inn, Lambs Conduit Street for those as like the details). The morning drive into Holborn was always used by the Sales Director to brief the Sales Managers by car phone so you really had to be on the road as mobiles were, in those days, fixed in the car. Still if I left home any later than 6 I knew I would never make the office before 10ish.