No matter what you do for a living, it's important to start your day right, such as with a relaxing cup of tea. Even sci-fi fascist drones enjoy tea. Though don't ask me how they drink it through the masks. Perhaps with a space straw?
If the masks were removed, you would see each man was brightly smiling. When your work helmet does the frowning for you, you're free to smile without looking goofy.
See all the stormtroopers take the bus to work so it's an interesting bus of men in underwear. Public transportation is awesome.
And if you want to get on the good side of a stormtrooper, get him a crumpet. Definitely a crumpet. Not a scone. Stormtroopers despise scones. And rebel resistance.