And that applies to all adults, whether or not they have a title. To adress a Person with first Name “Hey Joe” without Invitation is seen as really rude, not as sign of “equality” or something. (If anything, it’s the clichee of sleazy US used car salesman).
It’s also because relationships are personal matters, not work affairs, because Germans don’t live to work, they work to live. The idea that everybody at a workplace likes everybody and are “friends” and go out together is really weird. People at work are colleagues, to be treated with professional respect; friendships may form, or they may not. People might bring a cake for birthday, and get a token gift, but that’s all.
Also, the distinction is between friend and aquaintaince, not between Friend (for somebody you met an hour ago) and BFF (who you actually trust). The idea of having 50 or more “friends” or inviting a few hundred People to your wedding sounds … bizarre.
There are three Options to avoid “super small font size to squeeze Long Name on street sign”
Size on street signs is mandated, length of street sign is adapted.
Abbreviate for that instance.
Write in two lines: small font for titles, big font in bottom line for KING JR BLVD.
(We use Option 1, not just because of titles, but some People with double last names get to Long names, too).
In my City, they’ve started adding Little Grey signs with White letters underneath the official street sign, explaining who that Person was. I think that’s a good idea.