A coffeehouse style is what players who work hard to improve their skill at finding the objectively strongest moves in a position, having taken account of the objectively strongest moves available to the opponent, often disdain. Used by hustlers, by some recreational club players, and by many who play friendly blitz games, it is about playing what works in practice, in games with short or no time controls and which may be but are not necessarily played for money.
It includes playing moves that set traps that for some reason the opponent is likely to fall into. For example a classic example of a coffeehouse opening by Black is the Blackburne Shilling Gambit, 1 e4 e5, 2 Nf3 Nc6, 3 Bc4 Nd4. If White plays 4 0-0, 4 c3, 4 Nc3, or 4 Nxd4, he can get an advantage, whereas Black hopes that he will play 4 Nxe5, grabbing the pawn, after which he gets walloped by 4 ... Qg5, perhaps in the line 5 Nxf7 Qxg2, 6 Rf1 Qxe4+, 7 Be2 Nf3 mate.
But coffeehouse is not reducible to tactically trappy play and can be more subtle psychologically. For example if facing the line in the Alekhine Defence 1 e4 Nf6, 2 e5 Nd5, 3 c4 Nb6 White plays 4 a4, that move is not objectively weak but if it is played with a view to influencing Black to believe that White is weaker than he actually is, as if he were prone to lashing out aggressively with lots of pawn advances even when objectively unsound, it would be coffeehouse.
I would appreciate recommendations of titles not just on trappy coffeehouse openings, but on any aspect of how to play strong coffeehouse.
One book on coffeehouse is John Healy's Coffeehouse Chess Tactics (2010) and there is also John Emms's The Survival Guide to Competitive Chess (2005). What other titles are there?