One of the coolest grifter moves Henry Gondorff uses is the ol' watered-down gin trick. He busts in on Doyle Lonnegan's card game and makes sure no one takes him seriously because he's constantly slurping from a gin bottle.

But as he tells Johnny ahead of time,

HENRY GONDORFF: Always drink gin with a mark, kid. He can't tell if you cut it.

The smell of gin is so strong and distinct that it's impossible for someone sitting next to you to know that you've watered it down. This helps Henry seem super-drunk when he's actually just drinking mostly water.

All this is super-clever, but is it symbolic? Oh, yes indeed. It underlines the fact that Lonnegan is a man who traffics in preconceived notions, and that Henry Gondorff is a man who knows how to work against those preconceived notions.

Remember: Doyle Lonnegan is someone who's obsessed with his squeaky-clean image. He doesn't drink or chase women. He plays golf in a preppy cardigan. And he changed his biography so that people think he comes from money:

My guess is he's just trying to build himself a respectable image. He came out of Five Points, but he's telling everybody he was born in Forest Hills.

Lonnegan is exactly the kind of guy who would look down his nose at the convivial, obnoxious drunk that Henry Gondorff pretends to be. And while Lonnegan is busy rolling his eyes at Henry's faux-drunkenness, Henry can get busy cheating at cards.