Green’s Dictionary of Slang

bang adj.2

[abbr. bang-up adj. (2)]

1. (US) exciting.

[US](con. 1920s) ‘Harry Grey’ Hoods (1953) 157: I was frustrated. I needed a little of the bang action we had had in the old days. Things were too dull.

2. (US) a euph. for damn adj.

[Aus]N. Pulliam I Travelled a Lonely Land (1957) 230/1: bang – word of emphasis for practically everything, e.g., the whole bang kit and kaboodle.
[US]E. Torres Q&A 47: Right away I see things. I go to the movies with my old lady. Bang. Right away I tell her. John Wayne’s songs ain’t gonna sell, and he’s gonna start drinking.