Thing is, when I worked in a call centre (low paid and low skilled really, but a needs must out of work thing), I didn't have DCs I was happy to work Boxing day, double pay, and the employers werent shits, so noone was asked to do an 8 hour shift, the day was broken up into shorter ones - I did a relatively long shift of 7am - 12noon that year, most did 4 hours. I didn't really care about Boxing day, was home by 1 so didn't feel like i'd lost the day. Other employees with DCs didn't want to do that shift, but were happy to do the evening/night one or the New Years Day early start.
In retail, you get Christmas day and Easter Sunday off on the whole as few places are allowed to open on those days, every other day is up for grabs. They get the same holiday allowance, just not having the dictated to days of bank holidays.
In Hospitality, Christmas Day isn't a day off. Spare a thought for all those staff for people who've decided they can't be arsed cooking and are going out for christmas lunch. McDonalds is unlikely to join in on that because they are hardly a 'go to' place for Christmas Lunch, but most of the pubs and restaurants round here will be open. (How many families have a 'go for a pint while the turkey's being cooked' tradition on Christmas Day? That's all staffed)