People vehemently and strongly complain about wearing masks and it's known that it helps stopping you spread the disease to others. It provides little benefit to yourself, but can really help others. That's why I think it's inherently selfish.
I must admit to being surprised, all bar one of the customers in Sainsbury's today were wearing one. Maybe I'm wrong in this. It's just a really shame it had to become mandatory, a shame people in this country couldn't just be trusted to do the right thing.