I'm in my mid 30s and am working in my third organization.
At the last two places they didn't strongly enforce start or end time of work day, so I would typically start later than 9, work while I ate, and then be finished at 5 or maybe a little earlier.
My current company is a hospital (so open 24/7/365) and I work an office position (well free to WFH or in the office), doing largely independent work.
My boss INSISTS we start at 8, take a full hour for lunch, and don't end before 5.
It drives me insane. I don't mind working while I eat and really don't want a random free hour in the middle of the day. It takes me 10 minutes to eat lunch and I exercise before work. An hour isn't long enough to go do anything and make it back.
Every day I take the full hour on principle and feel resentful about it the entire time.
(Don't even get me started on the days she schedules “lunch meetings,” where we go to a restaurant, work an hour through lunch, and are expected to pay for our own food. 🤬).