Tegel is a nightmare. It was designed for maybe half the capacity it currently serves. Hopefully opening the BER airport will relieve some of that pressure. That they can handle such a high volume at all is remarkable. Do avoid Tegel if you can help it though.
In the other cities I've lived in, this article rings very true: you stop at crosswalks even when no cars are coming. Most people's houses are kept in immaculate order. (Exceptions of course exist.) "Deutcher pünklich heißt fünf Minuten früh sein" ("German punctuality means being five minutes early." — paraphrase of something I heard from a German friend of mine one time.)
City transit is remarkably accessible: I used to visit unfamiliar parts of cities and small towns occasionally armed with a map—an never with a phone with GPS. I never got lost. Transit maps and signage are clear and easy to understand.
I've visited Germany twice now since my two-year stay there. Each time I explore more—it's easy because of how much order there is in the transit to latch onto.
Berlin is a sort of internal exile colony for those who reject or are rejected by the German lifestyle but don’t for whatever reason want to leave Germany
There is a reason Berlin is famous for leaving work at 6 pm on a Friday, going to a club, and exiting only at 4am next Monday to go back to work.
Not saying this is good/healthy thing, but Berlin has history of being the hotspot for misfits. That is why a lot of Germans or even Europeans move here.
Problem is, Berlin isn't where the money is -- Munich is. So startups get started in Berlin and get funded in Munich?