Learn the custodian’s name. Character is mostly about who you bother to see.

Most people are perfectly polite to the staff they do not see, which is a way of not seeing them. Learning a name is a different act: it moves somebody from the scenery into the category of people whose day you are aware of. Character is largely a question of how wide that category is, and nobody widens it by accident.

Ask one person this week, and then use it: the custodian, the dinner staff, the security guard, the driver. Ask how their shift is going when you say it. Within a fortnight several people in the building will be glad to see you.