I was in the Tankstelle a few weeks back, just before the Wiesbaden game, and found the barman and customers very friendly. As said already, I wouldn't recommend going there wearing St Pauli or Celtic colours though. I didn't mention St Pauli, just spoke about HSV, Van der Vaart and Martin Joll.
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Der Junge von St. Pauli der hat die Welt geseh'n
in jedem fernen Hafen wollt' er vor Anker geh'n.
Die Sehnsucht trieb ihn weiter er glaubte an sein Glück,
doch es führten alle Wege nach St. Pauli zurück.