I've noticed that German speakers use the exclamation mark more liberally and it's used to indicate imperative mood, even though German verbs generally have a distinct imperative form.

You'll see this is common items like signs - "Keep off the grass!" or "Danger of electrocution!".

Over here, across the eastern German border, it's usually reserved for situations where you want to express frustration. People using it in the "enthusiastic" manner, that's apparently common in SV, come off as insincere.