When I applied for a job at this company, my last interview was with "Joe". For everyone else I got the first and last name. And email addresses were also firstname.lastname@example.com. But not for Joe. Joe's was just joe@example.com.

Same company after I was hired. I got on at about the same time as Peter-Michael. Whom we all called Peter-Michael. Because he was introduced as Peter-Michael. A few months in he revealed that he's only Peter-Michael at work. Everyone else just calls him Peter. It just happened like that because he used his full name on his application and then went with it.

I know several people who go with their second name as their usual name when around friends. Either because they like it more or sometimes because the parents chose that order because secondname-firstname sounded weird.