Starfleet officers often have trouble learning the unofficial rules of the station. There's no manual to study. You have to learn things as you go. A little different than... life on a starship.
Lt. Commander Worf:
When I served aboard the Enterprise, I always knew who were my allies, and who were my enemies.
Let's just say, DS9 has more shades of gray. And Quark definitely is a shade of... gray. He has his own set of rules, and he follows them diligently. Once you understand them, you understand Quark. I'd say that's true for... everyone here.
[he offers Worf a glass of raktajino]
You'll fit in, Commander. Just give it time.