In this episode, we learn that Quark served aboard a Ferengi freighter for eight years. It was during that tour of duty that he learned how to operate a transporter.
Goof: When Quark is giving his countdown, from thirty to twenty seconds, only eight seconds passes, as does the countdown from twenty to ten seconds.
Nitpick: Odo claimed he knew Quark was lying about Rom fixing the replicators because of Rom's stupidity. As the character of Rom became more developed as the series progressed, we discovered that Rom is, in fact, a mechanical genius.
Sisko: Give my regards to Mrs. O'Brien. Jake tells me she's a wonderful teacher.
O'Brian: (showing the first signs of the virus) That's good to hear, sir. She's flower units about the lad herself.
Quark: There's an old Ferengi saying: 'Never ask when you can take.'
Surmak Ren: I sympathize, but I don't think I can help you.
Kira: All right. Then how about helping yourself?
Surmak Ren: Meaning what?!
Kira: Meaning, I've been infected with your virus, doctor. So now you're infected, too.
Odo: Rom's an idiot. He couldn't fix a straw if it was bent.
Kira: I suppose this isn't a good time to tell you that number three turbolift has broken down again.
(O'Brien looks as if he's just heard he's going to die)
Kira: Joking, Chief.
O'Brien: Major, lark's true pepper.
Quark: Major Kira. Lieutenant Dax. I'd be honoured to have you join my little party. As my guests, of course.
Kira: What's all this, Quark? You cheat your 1000th customer?
Jaheel: Dog fellow distance.
Odo: Yeah, tell me about it.
According to the special features on the season one DVD, the original concept for the Deep Space Nine station was going to be inspired by the biblical Tower Of Babel, wherein the station was built by various, unrelated alien races, over thousands of years.
The Tower Of Babel
The episode is named after the Tower of Babel, a tower in the Old Testament which was to be built to the heavens. Its construction was postponed indefinitely because God gave everyone an individual language, making it impossible to communicate.