I guess if you look mean by default, you have to be more proactive and go talk to people to make them see you're not an asshole.. Which is not so easy when you're shy as hell ^^'
Not that the sentiment seems at all familiar, nope, never, nothing of the sorts...
Depending on your environment it becomes even more fun, as even a nominally friendly face is assumed to be constrained by a serious demeanour. Workplaces can drive that perception, alas.
(...scheint im Übrigen recht viele deutschsprachige Leute hier zu geben... :) )